GAISE - American Statistical Association

GAISE - American Statistical Association
Guidelines for Assessment and Instruction
in Statistics Education (GAISE)
College Report 2016
Committee:
Robert Carver (Stonehill College), Michelle Everson, co-chair (The Ohio State University), John
Gabrosek (Grand Valley State University), Nicholas Horton (Amherst College), Robin Lock (St.
Lawrence University), Megan Mocko, co-chair (University of Florida), Allan Rossman (Cal Poly
– San Luis Obispo), Ginger Holmes Rowell (Middle Tennessee State University), Paul Velleman
(Cornell University), Jeffrey Witmer (Oberlin College), and Beverly Wood (Embry-Riddle
Aeronautical University)
Citation: GAISE College Report ASA Revision Committee, “Guidelines for Assessment and Instruction in
Statistics Education College Report 2016,” http://www.amstat.org/education/gaise.
Endorsed by the American Statistical Association
July 2016
1
Contents
Committee: .......................................................................................................................................................... 1
Executive Summary ............................................................................................................................................ 3
Introduction......................................................................................................................................................... 4
Goals for Students in Introductory Statistics Courses .................................................................................... 8
Recommendations ............................................................................................................................................. 12
Suggestions for Topics that Might be Omitted from Introductory Statistics Courses ............................... 23
References .......................................................................................................................................................... 25
APPENDIX A: Evolution of Introductory Statistics and Emergence of Statistics Education Resources. 28
APPENDIX B: Multivariable Thinking.......................................................................................................... 34
APPENDIX C: Activities, Projects, and Datasets .......................................................................................... 43
APPENDIX D: Examples of Using Technology ............................................................................................. 66
APPENDIX E: Examples of Assessment Items ............................................................................................ 104
APPENDIX F: Learning Environments ....................................................................................................... 131
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Executive Summary
In 2005 the American Statistical Association (ASA) endorsed the Guidelines for Assessment and
Instruction in Statistics Education (GAISE) College Report. This report has had a profound
impact on the teaching of introductory statistics in two- and four-year institutions, and the six
recommendations put forward in the report have stood the test of time. Much has happened
within the statistics education community and beyond in the intervening 10 years, making it
critical to re-evaluate and update this important report.
For readers who are unfamiliar with the original GAISE College Report or who are new to the
statistics education community, the full version of the 2005 report can be found at
http://www.amstat.org/education/gaise/GaiseCollege_full.pdf and a brief history of statistics
education can be found in Appendix A of this new report.
The revised GAISE College Report takes into account the many changes in the world of statistics
education and statistical practice since 2005 and suggests a direction for the future of
introductory statistics courses. Our work has been informed by outreach to the statistics
education community and by reference to the statistics education literature.
We continue to endorse the six recommendations outlined in the original GAISE College Report.
We have simplified the language within some of these recommendations and re-ordered other
recommendations so as to focus first on what to teach in introductory courses and then on how to
teach those courses. We have also added two new emphases to the first recommendation. The
revised recommendations are:
1. Teach statistical thinking.
Teach statistics as an investigative process of problem-solving and decisionmaking.
Give students experience with multivariable thinking.
2. Focus on conceptual understanding.
3. Integrate real data with a context and purpose.
4. Foster active learning.
5. Use technology to explore concepts and analyze data.
6. Use assessments to improve and evaluate student learning.
This report includes an updated list of learning objectives for students in introductory courses,
along with suggested topics that might be omitted from or de-emphasized in an introductory
course. In response to feedback from statistics educators, we have substantially expanded and
updated some appendices. We also created some new appendices to provide details about the
evolution of introductory statistics courses; examples involving multivariable thinking; and ideas
for implementing the GAISE recommendations in a variety of different learning environments.
3
Introduction
Background
Much has changed since the ASA endorsed the Guidelines for Assessment and Instruction in
Statistics Education College Report (hereafter called the GAISE College Report) in 2005. Some
highlights include:
•
More students are studying statistics. According to the Conference Board on
Mathematical Sciences (CBMS) survey, 508,000 students took an introductory statistics
course in a two- or four-year college/university in the fall of 2010, a 34.7% increase from
2005. More than a quarter (27.0%) of these enrollments were at two-year colleges1.
Nearly 200,000 students took the Advanced Placement (AP) Statistics exam in 2015, an
increase of more than 150% over 2005. In addition, many high school students took the
AP course without taking the exam or took a non-AP statistics course. At the
undergraduate level, the number of students completing an undergraduate major in
Statistics grew by more than 140% between 2003 and 2013 and continues to grow
rapidly2.
•
Many students are exposed to statistical thinking in grades 6 – 12, because more state
standards include a considerable number of statistical concepts and methods. Many of
these standards have been influenced by the GAISE PreK – 12 report developed and
endorsed by the ASA3. In particular, the Common Core4 includes standards on
interpreting categorical and quantitative data and on making inferences and justifying
conclusions.
•
The rapid increase in available data has made the field of statistics more salient.
Many have heralded the flood of information now available. The Economist published a
special report on the “data deluge” in 20105. Statisticians such as Hans Rosling and Nate
Silver have achieved celebrity status by demonstrating how to garner insights from data6.
•
The discipline of Data Science has emerged as a field that encompasses elements of
statistics, computer science, and domain-specific knowledge7. Data science has been
described as the interplay between computational and inferential thinking8. It includes
the analysis of data types such as text, audio, and video, which are becoming more
1
http://www.ams.org/profession/data/cbms-survey/cbms2010-Report.pdf
http://www.amstat.org/education/curriculumguidelines.cfm
3
http://www.amstat.org/education/gaise/GAISEPreK-12_Full.pdf
4
http://www.corestandards.org/
5
http://www.economist.com/printedition/2010-02-27
6
Silver, N. (2012) The Signal and the Noise: Why So Many Predictions Fail—but Some Don’t. New York: Penguin
Books. Also see http://www.fivethirtyeight.com and http://www.gapminder.org.
7
http://magazine.amstat.org/blog/2015/10/01/asa-statement-on-the-role-of-statistics-in-data-science/
8
Jordan, M. (2016) Computational Thinking and Inferential Thinking: Foundations of Data Science eCOTS 2016.
Also see at https://www.causeweb.org/cause/ecots/ecots16/keynotes/jordan.
2
4
prevalent. There has been a parallel development of “analytics” as the study of extracting
information from big data—particularly with business and governmental applications.
•
More and better technology options for education have become widely available.
These include course management systems, automated homework systems, technology
for facilitating discussion and engagement, audience response systems, and videos now
used in many courses. Applets and other applications, such as Shiny apps coded in the R
programming language, that are designed to explore statistical concepts have come into
widespread use. Many general-purpose statistical packages have developed functions
specifically for teaching and learning.
•
Alternative learning environments have become more popular. These include online
courses, hybrid courses, flipped classrooms, and Massively Open Online Courses
(MOOCs). Many of these environments may be particularly helpful for supporting
faculty development.
•
Some have called for an update to the consensus introductory statistics curriculum
to account for the rich data that are available to answer important statistical questions.
•
Innovative ways to teach the logic of statistical inference have received increasing
attention. Among these are greater use of computer-based simulations and the use of
resampling methods (randomization tests and bootstrapping) to teach concepts of
inference9.
Concurrent with these changes, the ASA has promoted effective and innovative activities in
statistics education on several fronts, including the development and release of the following
reports:
•
Curriculum Guidelines for Undergraduate Programs in Statistical Science10, which
identifies the increased importance of teaching data science, real applications, more
diverse models and approaches, and the ability to communicate;
•
Statistical Education of Teachers11, a report that provides recommendations for
preparing teachers of statistics at elementary, middle, and high school levels, and is
meant to accompany the influential Mathematical Education of Teachers report12;
•
Qualifications for Teaching Introductory Statistics13, a statement produced by a joint
committee of the ASA and Mathematical Association of America, which recommends
that statistics teachers have at least the equivalent of two courses in statistical methods
and some experience with data analysis beyond the material taught in introductory
courses;
9
G.W. Cobb’s plenary at USCOTS 2005 presentation and later article http://escholarship.org/uc/item/6hb3k0nz .
http://www.amstat.org/education/pdfs/guidelines2014-11-15.pdf
11
http://www.amstat.org/education/SET/SET.pdf
12
http://www.cbmsweb.org/MET2/met2.pdf
13
http://www.amstat.org/education/pdfs/TeachingIntroStats-Qualifications.pdf
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5
•
ASA’s Statement on p-Values14, which puts forward several important principles about
hypothesis testing based on consensus among those in the statistical community, in an
effort to improve the ways in which the statistical results of scientific studies are reported
and interpreted.
Recommendations
We are gratified by how well the GAISE recommendations from 2005 and those of the 1992
Cobb report have held up over time. We attribute this to the broad, general, useful, and universal
nature of the framework for instruction.
We continue to endorse the six GAISE recommendations put forth in 2005. We have
reordered the recommendations so the first two address what to teach and the next four concern
how to teach. We have also simplified and clarified some of the recommendations. The revised
recommendations are
1.
2.
3.
4.
5.
6.
Teach statistical thinking.
Focus on conceptual understanding.
Integrate real data with a context and a purpose.
Foster active learning.
Use technology to explore concepts and analyze data.
Use assessments to improve and evaluate student learning.
In addition to these six recommendations, which remain central, we suggest two new emphases
for the first recommendation (teach statistical thinking) that reflect modern practice and take
advantage of widely available technologies:
a. Teach statistics as an investigative process of problem-solving and decision-making.
Students should not leave their introductory statistics course with the mistaken
impression that statistics consists of an unrelated collection of formulas and methods.
Rather, students should understand that statistics is a problem-solving and decisionmaking process that is fundamental to scientific inquiry and essential for making sound
decisions.
b. Give students experience with multivariable thinking. We live in a complex world in
which the answer to a question often depends on many factors. Students will encounter
such situations within their own fields of study and everyday lives. We must prepare our
students to answer challenging questions that require them to investigate and explore
relationships among many variables. Doing so will help them to appreciate the value of
statistical thinking and methods.
14
Wasserstein, R. L., and Lazar, N. A. (2016), “The ASA’s Statement on p-Values: Context, Process, and Purpose,”
The American Statistician, 70. http://dx.doi.org/10.1080/00031305.2016.1154108.
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Scope
There is no single introductory statistics course. The variety of courses reflects a wide range of
needs.
•
Some introductory courses address statistical literacy, while others focus on statistical
methods. This distinction is sometimes referred to as courses for consumers versus those
for producers of analyses.
•
Introductory statistics courses target many different student audiences. There are
different needs at different institutions, from elite universities to community colleges,
with varying access to technology and support. Some statistics courses aim for a general
student audience, while others are targeted at students in the life sciences, at business
students, at future engineers, or at mathematics majors. There is a demand in some of
these fields for examples and topical coverage tailored to the specific needs of the applied
discipline.
•
Prerequisites differ among introductory statistics courses, the primary distinction being
that some require calculus but most require no more than high school algebra.
•
Class sizes range from small courses of a dozen students that might be taught in a
computer lab to large lecture courses for hundreds of students to massively open online
courses (MOOCs) taught to thousands asynchronously.
We believe that the six GAISE recommendations apply to the many variations of introductory
statistics courses, although the specifics of how they are implemented in these courses will vary
to suit the situation. Despite the fact that this report focuses on introductory courses, we believe
that the GAISE recommendations also apply to statistics courses beyond the introductory level.
We urge instructors to consider applying these recommendations throughout undergraduate
statistics courses, including courses in statistical practice, statistical computing, and statistical
theory.
Support for Implementation
Throughout the development of this report, we have tried to maintain realistic expectations while
setting aspirational goals. We hope that this report can help instructors of introductory statistics
improve their courses. We recognize that instructors face constraints that can make innovation
challenging, but we believe that any statistics course can benefit from incremental changes that
produce closer alignment with the six recommendations.
To facilitate innovation, this report includes substantially expanded and revised appendices that
provide many examples of
•
•
•
activities and datasets to illustrate active learning of statistical thinking,
assessment items, instruments, assignments, and rubrics,
technology tools for exploring concepts and analyzing data, and
7
•
suggestions by which the guidelines can be fulfilled in various learning environments
(face-to-face, flipped, online, etc.).
Coursess
Goals for Students in Introductory Statistics Course
The desired result of all introductory statistics courses is to produce statistically educated
students, which means that students should develop the ability to think statistically.
The following goals reflect major strands in the collective thinking expressed in the statistics
education literature. They summarize what a student should know and understand at the
conclusion of a first course in statistics. Achieving this knowledge will require learning some
statistical techniques, but mastering specific techniques is not as important as understanding the
statistical concepts and principles that underlie such techniques. Therefore, we are not
recommending specific topical coverage.
1. Students should become critical consumers of statistically-based results reported in
popular media, recognizing whether reported results reasonably follow from the study
and analysis conducted.
2. Students should be able to recognize questions for which the investigative process in
statistics would be useful and should be able to answer questions using the investigative
process.
3. Students should be able to produce graphical displays and numerical summaries and
interpret what graphs do and do not reveal.
4. Students should recognize and be able to explain the central role of variability in the field
of statistics.
5. Students should recognize and be able to explain the central role of randomness in
designing studies and drawing conclusions.
6. Students should gain experience with how statistical models, including multivariable
models, are used.
7. Students should demonstrate an understanding of, and ability to use, basic ideas of
statistical inference, both hypothesis tests and interval estimation, in a variety of settings.
8. Students should be able to interpret and draw conclusions from standard output from
statistical software packages.
9. Students should demonstrate an awareness of ethical issues associated with sound
statistical practice.
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Goal 1: Students should become critical consumers of statistically-based results reported in
popular media, recognizing whether reported results reasonably follow from the study and
analysis conducted.
To be a critical consumer of statistically-based results, it is necessary to understand the
components that produced them: the design of the investigation, the data, its analysis, and its
interpretation. Identifying the variables in a study, which includes consideration of the
measurement units, is a necessary step to inform judgments or comparisons. Identifying the
subjects (cases, observational units) of a study and the population to which the results of an
analysis can be generalized helps the consumer to recognize whether the reported results can
reasonably support the conclusions claimed for an analysis. Being able to interpret displays of
data (tables, graphs, and visualizations) and statistical analyses also informs the consumer about
the reasonableness of the claims being presented.
Goal 2: Students should be able to recognize questions for which the investigative process in
statistics would be useful and should be able to answer questions using the investigative process.
The investigative process begins with a question that can be translated into one or more
statistical questions – questions that can be investigated using data. While many questions do not
have simple yes or no answers, knowing how to obtain or generate data that are relevant to the
goals of a study is crucial to providing useful information that supports decision-making in the
sciences, business, healthcare, law, the humanities, etc. Understanding and applying the
principles of representative sampling for an observational study or designing an experiment is
critical to the investigative process. Understanding and, when possible, controlling for the
impact of other variables is important.
Once high quality data have been collected, meaningful graphs and numerical summaries
(generally created using technology) shed light on the question under study. These summaries
help to identify statistical inference procedures that are appropriate to the question. The results
of the data analysis, and any limitations, need to be clearly communicated.
Goal 3: Students should be able to produce graphical displays and numerical summaries and
interpret what these do and do not reveal.
Data analysis involves much more than constructing a confidence interval or finding a p-value.
Graphical displays of data provide information on the distribution of data values, relationships
among variables, and outliers. With the advent of large datasets – often from observational
studies that may not be a random sample from a defined population, making standard inferential
techniques inappropriate – the proper use of graphical displays is critical. Using software to
produce graphical displays makes visualization of large data sets relatively easy. Important
univariate graphical displays include histograms, boxplots, dotplots, and bar charts. Bivariate
graphical displays include scatterplots, clustered and stacked bar charts, and comparative
histograms and boxplots. Additional variables can often be added to a graphical display (for
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example, separately colored points and regression lines for males and females can be included in
a scatterplot that relates age to height for children 3 years to 18 years).
Goal 4: Students should recognize and be able to explain the central role of variability in the field
of statistics.
Variability is a key characteristic of data that underlies statistical associations and inference.
Identifying the sources of variability in a statistical study is an important consideration.
Graphical displays and numerical summaries help to illustrate and describe distributions of data
(shape, center, variability, and unusual observations) and to select appropriate inference
techniques. The role of sampling variability is the bridge to making comparisons and drawing
inferences. At the introductory level, this includes an understanding of univariate (and perhaps
bivariate) sampling distribution and/or randomization distribution models, and the role of
features such as sample size, variability in the statistics, and distributional shape in these models.
Understanding how results vary from sample to sample is a challenging topic for many students.
Goal 5: Students should recognize and be able to explain the central role of randomness in
designing studies and drawing conclusions.
The mathematical understanding of “random” (not synonymous with haphazard or unplanned) is
fundamental to the role that randomness plays in statistical studies. Distinction of probabilistic
sampling techniques from non-probabilistic ones help to recognize when it is appropriate for the
results of surveys and experiments to be generalized to the population from which the sample
was taken. Similarly, random assignment in comparative experiments allows direct cause-andeffect conclusions to be drawn while other data collection methods usually do not.
Goal 6: Students should gain experience with how statistical models, including multivariable
models, are used.
Understanding the role of models in statistics is a critical skill for being able to investigate the
distribution of data values and the relationships between variables. The first recommendation of
the GAISE report is to teach statistical thinking. One of the key features of statistical thinking is
to understand that variables have distributions. Models help us describe the distribution of
variables, especially the distribution of one or more variables conditional upon the values of one
or more other variables.
It is important to understand that two variables may be associated and that statistical models can
be used to assess the strength and direction of the association. Bivariate models that relate two
variables – such as the regression model relating a dependent quantitative response variable to an
independent quantitative explanatory variable – are building blocks for more complicated
multivariable models. While the details of these more complicated models may be beyond most
introductory courses, it is important that students have an appreciation that the relationship
between two variables may depend on other variables. Multivariable relationships, illustrating
Simpson’s Paradox or investigated via multiple regression, help students discover that a two-way
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table or a simple regression line does not necessarily tell the entire (or even an accurate) story of
the relationship between two variables.
Goal 7: Students should demonstrate an understanding of, and ability to use, basic ideas of
statistical inference, both hypothesis tests and interval estimation, in a variety of settings.
Statistical inference involves drawing conclusions about a population from the information
contained in a sample. Often this involves calculation of sample statistics to make inferences
about population parameters either through estimation (for example, a confidence interval to
estimate the proportion of voters who have a favorable impression of the President of the United
States) or testing (for example, a hypothesis test to determine if the mean time to headache relief
is less for a new drug than a current drug). At least as important as calculating confidence
intervals and p-values is understanding the concepts underlying statistical inference.
Understanding the limitations of inferential procedures, including checking assumptions, and the
effect of sample size and other factors, are important to assessing the practical significance of
results and that if you conduct multiple tests, some results might be significant just by chance.
Being able to identify which inferential methods are appropriate for common one-sample and
two-sample parameter problems helps develop statistical thinking skills. Providing ample
opportunity to practice drawing and communicating appropriate conclusions from inferential
procedures allows students to demonstrate understanding of statistical inference.
Goal 8: Students should be able to interpret and draw conclusions from standard output from
statistical software.
Modern data analysis involves the use of statistical software to store and analyze (potentially
large) datasets. While there may be value to performing some calculations by hand, it is
unrealistic to analyze data without the aid of software for all but the smallest datasets. At a
minimum, students should interpret output from software. Ideally, students should be given
numerous opportunities to analyze data with the best available technology (preferably, statistical
software).
Goal 9: Students should demonstrate an awareness of ethical issues associated with sound
statistical practice.
As data collection becomes more ubiquitous, the potential misuse of statistics becomes more
prevalent. Application of proper data collection principles, including human subjects review and
the importance of informed consent, are central to the effective and ethical use of statistical
methods. Relying on statistical methods to inform decisions should not be confused with
abusing data to justify foregone conclusions. With large datasets containing many variables,
especially from observational studies, understanding of confounding and multiple testing false
positive rates becomes even more relevant.
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Recommendations
The American Statistical Association continues to endorse the six recommendations put forward
in the original GAISE College Report. The intent of these recommendations is to help students
attain the learning goals described previously. Much has changed since 2005; therefore, we have
reworded some recommendations to highlight new emphases. We have also reordered the
recommendations so that the first two focus on what to teach in the introductory courses and the
next four focus on how to teach the courses. In the sections below, we provide additional
explanations and suggestions regarding the recommendations; these have been updated and
expanded from the 2005 report.
Recommendation 1: Teach statistical thinking.
An introductory course is also a terminal course for many students. As such, it is important that
we think carefully about what our focus should be in this course: what do we want to teach,
what skills do we want our students to have when they leave the course? Will they use statistics
in follow-up courses and careers, and will they be consumers of statistical information presented
in the news and abounding in everyday life?
We propose that it is essential to work on the development of skills that will allow students to
think critically about statistical issues and recognize the need for data, the importance of data
production, the omnipresence of variability, and the quantification and explanation of variability.
In other words, statistical thinking – the type of thinking that statisticians use when approaching
or solving statistical problems – should be taught and emphasized in introductory courses (see
Wild and Pfannkuch 1999 and Chance 2003 for more discussion of statistical thinking). As part
of the development of statistical thinking skills, it is crucial to focus on helping students become
better educated consumers of statistical information by introducing them to the basic language
and the fundamental ideas of statistics, and by emphasizing the use and interpretation of statistics
in everyday life. We want our students to become statistically literate (for more on statistical
literacy, see Utts 2003, 2010, 2015).
We urge instructors of statistics to emphasize the practical problem-solving skills that are
necessary to answer statistical questions. We should model statistical thinking for our students
throughout the course, rather than present students with a set of isolated tools, skills, and
procedures. Effective statistical thinking requires seeing connections among statistical ideas and
recognizing that most statistical questions can be solved with a variety of procedures and that
there is often more than one acceptable solution.
Expanding upon the metaphor introduced by Shoenfeld (1998), Garfield, delMas, and Zieffler
(2012) proposed the need to rethink the teaching of the introductory courses so that students
leave the course with an understanding not just of routine procedures but of the “big picture of
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the statistical process that will allow them to solve unfamiliar problems and to articulate and
apply their understanding” (p.885). These authors argue that we should refrain from teaching
our students merely how to follow recipes and should instead teach them how to really cook.
Using a “cooking analogy,” they explain that someone who can really “cook” not only
understands how to follow recipes but can make easy adjustments at a moment’s notice by
knowing exactly what to focus on and look for when attempting to assemble not just a single
dish but a full meal.
The following carpentry story provides another illustration of statistical thinking and an
alternative to the “cooking analogy:”
In week 1 of the carpentry (statistics) course, we learned to use various kinds of planes
(summary statistics). In week 2, we learned to use different kinds of saws (graphs).
Then, we learned about using hammers (confidence intervals). Later, we learned about
the characteristics of different types of wood (tests). By the end of the course, we had
covered many aspects of carpentry (statistics). But I wanted to learn how to build a table
(collect and analyze data to answer a question) and I never learned how to do that. We
should teach students that the practical operation of statistics is to collect and analyze
data to answer questions.
As a part of the overarching emphasis to teach statistical thinking, we propose that the
introductory course teach statistics as an investigative process of problem-solving and decisionmaking. We also propose that all students be given experience with multivariable thinking in the
introductory course. We expand on each of these ideas below.
Teach statistics as an investigative process of problem-solving and decision-making.
We urge instructors to emphasize the investigative nature of statistics throughout their courses.
We hope that doing so can avoid the unfortunate, but not uncommon, reality that many students
leave their introductory course thinking of statistics only as a disconnected collection of methods
and tools.
In their early work on statistical thinking, Wild and Pfannkuch (1999) summarize the
investigative cycle with the acronym PPDAC (Problem, Plan, Data, Analysis, Conclusion). A
nice illustration of this cycle appears in classrooms throughout New Zealand:
http://new.censusatschool.org.nz/wp-content/uploads/2012/11/data-detective1.pdf.
Another way of thinking about the statistical investigative cycle is provided in the GAISE PreK12 Report (Franklin et al. 2007), where this process is laid out in four stages:
1.
2.
3.
4.
Formulate questions.
Collect data.
Analyze data.
Interpret results.
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We do not advocate one particular conception of the investigative process, nor do we
recommend a specific number of stages or steps in this process; we do strongly recommend that
instructors emphasize the investigative nature of the field of statistics throughout their
introductory course. Mentioning the investigative process at the beginning of the course but then
treating various course topics in a compartmentalized manner does not help students to see the
big picture. We recommend that throughout the entire introductory course, instructors illustrate
the complete investigative cycle with every example/exercise presented, starting with the
motivating question that led to the data collection and ending with the scope of conclusions and
directions for future work.
As we think about engaging students in the investigative process, we hope to create mental habits
such as the six mental habits described by Chance (2002):
1.
2.
3.
4.
5.
6.
Understand the statistical process as a whole.
Always be skeptical.
Think about the variables involved.
Always relate the data to the context.
Understand (and believe) the relevance of statistics.
Think beyond the textbook.
De Veaux and Velleman (2008) reiterate this approach in their suggestion that introductory
statistics courses should involve students in the process of proposing questions, testing
assumptions, and drawing conclusions from data. Statistics involves an investigative process of
problem-solving and decision-making, which makes it a fundamental discipline in advancing
both scientific discoveries and business and personal decisions.
One way of incorporating the investigative process into a first statistics course is to ask students
to complete projects that involve study design, data collection, data analysis, and interpretation.
We can also attempt to include activities in our courses that involve students in different parts of
the investigative cycle. We might further share examples of real studies that are reported in the
news or in journal articles and engage our students in discussion of the conclusions drawn from
these studies and whether such conclusions are valid in light of the methods used to gather and
explore the data.
Give students experience with multivariable thinking.
When students leave an introductory course, they will likely encounter situations within their
own fields of study in which multiple variables relate to one another in intricate ways. We
should prepare our students for challenging questions that require investigating and exploring
relationships among more than two variables.
Kaplan (2012) has criticized the tendency for the introductory course to focus on simple
questions about how two groups differ or about how two variables are correlated. Such
14
questions, while interesting, do not necessarily prepare students to tackle more complicated realworld questions that involve more than one or two variables. Horton (2015) writes that “the lack
of application for simple multivariable methods is a major limitation of too many of our courses”
(p. 141). To illustrate the power of multivariable thinking and modeling, consider an example
that shows how accounting for the percentage of students taking the SAT exam in a state
completely changes the conclusion that would be drawn about the relationship between average
SAT score and average teacher salary in the state (see Appendix B for more details). This
example illustrates that helping students to think about three or more variables does not
necessarily require introducing multiple regression; simple graphical displays or techniques such
as stratification can suffice.
De Veaux (2015) has also challenged statistics educators to think about how to improve
introductory courses by, among other things, emphasizing the multivariate nature of the
discipline. He calls for the motivation of univariate questions to arise from more complex
models, and he illustrates how this can be done with examples that highlight (a) the relationship
between diamond price and color, and how this relationship changes when carat weight is taken
into account, and (b) the relationship between the presence or absence of a fireplace and the price
of a home in New England, and how this relationship also changes markedly when square
footage is taken into account.
Kaplan’s, Horton’s, and De Veaux’s examples illustrate that instructors do not need to go into
detail about multivariable modeling in order to provide students with an appreciation for the need
to consider how multiple variables interact. Students can explore and investigate such
relationships by being presented with interesting questions from rich datasets and then producing
appropriate graphical displays. These examples also give rise to discussions of how confounding
plays an important role in determining the appropriate scope of conclusions to be drawn from
such data. (See http://community.amstat.org/stats101/home for the STAT101 toolkit for
instructors of introductory statistics courses.)
Suggestions for teachers:
•
•
•
Model statistical thinking for students by working examples and explaining the questions
and processes involved in solving statistical problems from conception to conclusion.
Give students practice with developing and using statistical thinking. This should include
open-ended problems and projects, in addition to real-life scenarios with multiple
variables that can also help students appreciate the role that statistics plays in everyday
life. Provide students with examples of real studies and, within each study, discuss the
research questions that guided the study, the collection of the data, the analysis of the
results, the conclusions that were reached, and the scope of the conclusions.
Begin most examples throughout the course by considering basic issues such as
identifying observational units and variables, classifying variables as categorical or
quantitative, and considering whether the study made use of random sampling, random
assignment, both, or neither.
15
•
•
•
Offer students considerable practice with selecting an appropriate technique to address a
particular research question, rather than telling them which technique to use and merely
having them implement it.
Use technology and show students how to use technology effectively to manage data,
explore and visualize data, perform inference, and check conditions that underlie
inference procedures.
Assess and give feedback on students’ statistical thinking (also see Recommendation 6
below) as they progress through the course. In the appendices to this report, we present
examples of projects, activities, and assessment instruments and questions that can be
used to develop and evaluate statistical thinking.
Recommendation 2: Focus on conceptual understanding.
Earlier, we highlighted important learning objectives that an instructor hopes their students will
achieve. It can be challenging to present material in a way that facilitates students’ development
of more than just a surface level understanding of important concepts and ideas.
Certainly, an introductory course will involve some computation, though most should be
facilitated by technology. It is desirable for students to be able to make decisions about the most
appropriate ways to visualize, explore, and, ultimately, analyze a set of data. It will not be
helpful for students to know about the tools and procedures that can be used to analyze data if
students don’t first understand the underlying concepts. Having a good understanding of the
concepts will make it easier for students to use necessary tools and procedures to answer
particular questions about a dataset.
Procedural steps too often claim students’ attention that an effective teacher could otherwise
direct toward concepts. Students with a good conceptual foundation from an introductory course
will be well-prepared to study additional statistical techniques in a second course.
Suggestions for teachers:
•
•
•
•
•
View the primary goal as to discover and apply concepts.
Focus on students’ understanding of key concepts, illustrated by a few techniques, rather
than covering a multitude of techniques with minimal focus on underlying ideas.
Pare down content of an introductory course to focus on core concepts in more depth.
Perform most computations using technology to allow greater emphasis on understanding
concepts and interpreting results.
Although the language of mathematics provides compact expression of key ideas, use
formulas that enhance the understanding of concepts, and avoid computations that are
divorced from understanding.
16
Recommendation 3: Integrate real data with a context and a
purpose.
Using real data in context is crucial in teaching and learning statistics, both to give students
experience with analyzing genuine data and to illustrate the usefulness and fascination of our
discipline. Statistics can be thought of as the science of learning from data, so the context of the
data becomes an integral part of the problem-solving experience. The introduction of a data set
should include a context that explains how and why the data were produced or collected.
Students should practice formulating good questions and answering them appropriately based on
how the data were produced and analyzed.
Using real data sets of interest to students is a good way to engage students in thinking about the
data and relevant statistical concepts. Neumann, Hood and Neumann (2013) explored reflections
of students who used real data in a statistics course and found the use of real data was associated
with students’ appreciating the relevance of the course material to everyday life. Further,
students indicated that they felt the use of real data made the course more interesting.
Suggestions for teachers:
•
•
•
•
•
•
•
•
•
Use real data from studies to enliven your class, motivate students, and increase the
relevance of the course to the real world.
Use data with a context as the catalyst for exploration, generating the questions, and
informing interpretations to conclusions.
Make sure questions used with data sets are of interest to students so they can be easily
motivated. Take the time to explain why we are interested in this type of data and what it
represents. Note: Few data sets interest all students, so instructors should use data from a
variety of contexts.
Use class-generated data to formulate statistical questions and plan uses for the data
before developing the questionnaire and collecting the data. For example, ask questions
likely to produce different shaped histograms, or use interesting categorical variables to
investigate relationships. It is important that data gathered from students in class does not
contain information that could be embarrassing to students and that students’ privacy is
maintained.
If data entry is a part of the course, get students to practice entering raw data using a
small data set or a subset of data, rather than spending time entering a large data set.
Use statistical software to analyze larger datasets that are available electronically.
Use subsets of variables in different parts of the course, but integrate the same data sets
throughout. (Example: Use side-by-side boxplots to compare two groups, then use twosample t-tests on the same data. Use histograms to investigate shape, and then later in the
course to verify conditions for hypothesis tests. Encourage students to explore how
multiple variables in the data set relate to one another.)
Minimize the use of hypothetical data sets to illustrate a particular point or to assess a
specific concept.
See the Appendices C, D, and E for examples of good ways to use data in class activities,
homework, projects, tests, etc.
17
•
•
•
•
•
•
Search web data repositories, textbooks, journal articles, software packages, and websites
with surveys/polls for good raw data or summarized data to use in class activities. Expect
new sources of data to become available each year. Appendix C includes a list of useful
websites with data repositories.
Expose students to data that they interact with on a regular basis, such as data generated
by online social networks or data tracked regularly on mobile smart devices (Gould
2010).
Be alert to the messiness of much real data before using it in a course; better still expose
students to typical issues such as missing observations, inconsistent identifiers, and the
challenges of merging data from multiple sources (Carver and Stephens, 2014).
Introduce students to interactive data visualization websites (Ridgway, in press), such as
the Gapminder software of Hans Rosling (http://www.gapminder.org) or the website
provided by the Office of National Statistics in the UK to explore commuting patterns
(http://www.neighbourhood.statistics.gov.uk/HTMLDocs/dvc193/).
Consider opportunities to align the data sources you select to institutional objectives at
your school. For example, you may want to seek out datasets related to expanding
students’ global awareness, focusing on social justice concerns, or exploring issues of
local importance.
Seek out real data directly from a practicing research scientist through a journal or at
one’s home institution.
Recommendation 4: Foster active learning.
Active learning has been described as a set of approaches that involve students in doing things
and thinking about the things they are doing (Bonwell and Eison 1991). Using active learning
methods in class allows students to discover, construct, and understand important statistical ideas
as well as to engage in statistical thinking. Other benefits include the practice students get
communicating in statistical language and learning to work in teams to solve problems.
Activities provide teachers with a method of assessing student learning and provide feedback to
the instructor on how well students are learning. A recent meta-analysis (Freeman et al. 2014)
concludes that there are distinct advantages in terms of course outcomes when active learning is
employed in STEM courses.
Instructors should not underestimate the learning gains that can be achieved with activities or
overestimate the value of lectures to convey information. Embedding even brief activities within
lectures can break the natural occasional dips in attention associated with passive or minimallyengaged listeners.
Whereas some rich activities can take an entire class session, many valuable activities need not
take much time. A think-pair-share discussion or prediction exercise may take only 2-3 minutes,
which might otherwise be spent in redundant lecturing due to audience inattention. Collecting
on-the-spot data may take more time but reaps benefits beyond the single activity that prompted
the collection (see Recommendation 3). Appendix C contains many activities that may replace
18
(or drastically reduce) some lectures and Appendix F has additional suggestions specifically
geared to implementing this recommendation in large classes.
Suggestions for teachers:
•
•
•
•
•
•
Ground activities in the context of real data with a motivating question. Do not “collect
data to collect data” for its own sake.
Consider the student need for physical explorations (e.g., die rolling, card drawing) prior
to the use of computer simulations to illustrate or practice concepts.
Encourage predictions from students about the results of a study that provides the data for
an activity before analyzing the data. This motivates the need for statistical methods. (If
all results were predictable, we would not need either data or statistics.)
Avoid activities that lead students step-by-step through a list of procedures. Instead,
allow students to discuss and think about the data and the problem.
When planning activities, be sure there is enough time to explain the problem, let the
students work through the problem, and wrap-up the activity during the same class
period.
Consider low-/no-stakes peer assessment (where students comment on or rate a
classmate’s work) within class to provide quick feedback and to improve the quality of
final assessments.
Recommendation 5: Use technology to explore concepts and
analyze data.
Technology has changed the practice of statistics and hence should change what and how we
teach. By technologies, we refer to a range of hardware and software that can do far more than
handle the computational burden of analysis. By adopting the best available tools (subject to
institutional constraints), we allow students to do analysis more easily and therefore open up
time to focus on interpretation of results and testing of conditions, rather than on computational
mechanics. Technology should aid students in learning to think statistically and to discover
concepts. It should also facilitate access to real (and often large) datasets, foster active learning,
and embed assessment into course activities.
Statistics is practiced with computers and usually with specially designed computer software.
Students should learn to use a statistical software package if possible. Calculators can provide
some limited functionality for smaller datasets, but their use should be supplemented with
experience reading typical computer results. Regardless of the tools used, it is important to
view the use of technology not just as a way to generate statistical output but as a way to
explore conceptual ideas and enhance student learning. We caution against using technology
merely for the sake of using technology or for pseudo-accuracy (carrying out results to many
decimal places). Not all technology tools will have all desired features.
19
When computers are not available to all students at all times, experience with computers could
include one or more of the following:
•
•
•
A brief introduction to a statistical software package, for example in a computer lab.
Watching an instructor demonstrate the use of a statistical software package in the
context of a statistical investigation.
Reading generic “computer output” designed to resemble computer package results, but
not specifically reproducing any of the major packages. This can be coupled with
questions that probe student understanding. (e.g., what is the regression equation?)
For example, an instructor might demonstrate how to estimate a regression equation using a
statistical package, then provide students with copies of the resulting regression table and
residual plots, and ask students to summarize the results and assess model conditions.
Alternatively, an instructor might create an exploratory graph, elicit questions or suggestions
from the class, modify the graph in real time, and share the results from the final analysis.
Technology tools should also be used to help students visualize concepts and develop an
understanding of abstract ideas by simulations. Some tools offer both types of uses, while in
other cases, a statistical software package may be supplemented by web applets.
We note that technology continues to evolve rapidly. Many smart phones or tablets can provide
access to online statistical software when sufficient internet access is available. We also note
that institutions and courses vary widely in funding and the resources necessary to support this
recommendation. The catchphrase should be “use the best available technology.”
Some technologies available:
(See Appendix D for in-depth discussion and examples.)
Interactive applets
Statistical software
Web-based resources, including
o sources of experimental, survey, and observational data
o online texts
o data analysis routines
Games and other virtual environments
Spreadsheets
Graphing calculators
•
•
•
•
•
•
Suggestions for teachers:
•
Perform routine computations using technology to allow greater emphasis on
interpretation of results.
20
•
•
•
•
•
•
•
•
•
View the primary goal as discovering concepts rather than covering methods.
Implement computer-intensive methods to find p-values and de-emphasize t-, normal
and other probability tables. Analyze large, real, data sets.
Generate and modify appropriate statistical graphics, including relatively recent
innovations like motion charts and maps.
Perform simulations to illustrate abstract concepts.
Explore “what happens if... ” questions.
Create reports.
Harness the impact of interactive, real-time visualizations to engage students in the
investigative process and in multivariable thinking.
Use real-time response systems for formative assessment.
Use games and virtual environments to engage students, teach concepts and gather
data.
Considerations for teachers when selecting technology tools:
•
•
•
•
•
•
•
•
•
•
Ease of data entry, ability to import data in multiple formats
Interactive capabilities
Support of specific pedagogical goals
Dynamic linking between data, graphical, and numerical analyses
Ease of use for particular audiences (including those with visual or hearing impairments)
Availability to students, portability
Support for reproducible analysis and integration with word-processing and presentation
software
Support for merging data from multiple sources and data management
Functional consistency across platforms (i.e. consistency for Mac and Windows users
where students have laptops)
Tablet and mobile support
Recommendation 6: Use assessments to improve and evaluate
student learning.
Students will value what you assess; therefore, assessments need to be aligned with learning
goals. Assessments need to focus on understanding key ideas, and not just on skills, procedures,
and computed answers. Being able to calculate a p-value is not enough; students need to be able
to draw conclusions about the research question from a p-value and also explain the reasoning
process that leads from the p-value to the conclusion.
Useful and timely feedback is essential for assessments to lead to learning. There are two types
21
of assessment. Formative assessment aims to monitor and improve student learning by
providing students with ongoing feedback about their learning during the learning process. Such
feedback can also help instructors to improve their teaching by focusing on ideas and concepts
that are most challenging for students. Examples of formative assessments include quizzes,
homework assignments, and minute papers. Summative assessment, in contrast, focuses on
evaluating student learning at the end of instruction. Examples of summative assessments
include exams (such as a midterm or a final) and final course projects. Formative and
summative assessments are certainly not mutually exclusive categories in that good assessments
can both promote and evaluate student learning. We encourage instructors to maximize
opportunities to include formative assessments into their courses rather than focus exclusively on
summative assessments.
Types of assessment:
The practicality of any given type of assessment will vary with each type of course. However, it
is possible, even in large classes, to implement good assessments. Below, we list several
possible assessment methods that can be used in a course, and Appendix E includes a variety of
different assessment items.
•
•
•
•
•
•
•
•
Homework questions
Quizzes and exams
Projects
Activities
Oral presentations
Written reports
Minute papers
Article critiques
Suggestions for teachers:
•
•
•
•
•
•
•
Integrate assessment as an essential component of the course. Assessment tasks that are
well-coordinated with what the teacher is doing in class are more effective than tasks that
focus on what happened in class two weeks earlier.
Written assignments such as minute papers, lab reports or even semester long projects
can help students strengthen their knowledge of statistical concepts and practice good
communication skills.
Use a variety of assessment methods to provide a more complete evaluation of student
learning.
Use items that focus on choosing good interpretations of graphs or selecting appropriate
statistical procedures.
Have students interpret or critique articles in the news and graphs in media.
Encourage students to work in groups on some low-stakes assessments (e.g., quizzes) to
promote learning from each other.
Collaborative projects have been identified by the Association of American Colleges and
Universities (AAC&U) as a high impact practice (AAC&U, 2008).
22
•
Consider assessing statistical thinking using student projects and open-ended
investigative tasks.
Suggestions for student assessment in large classes:
•
•
•
•
Use small group projects instead of individual projects.
Use peer review of projects to provide feedback and improve projects before grading.
Use discussion sections for student presentations.
Incorporate real-time response systems (e.g., clickers) in the classroom in order to
provide students with opportunities to demonstrate their understanding of course material
and instructors with feedback about possible misconceptions or misunderstanding about
course material.
Resources on assessment:
•
•
•
http://www.amstat.org/publications/jse/v2n1/garfield.html
http://www.amstat.org/publications/jse/v5n3/chance.html
https://apps3.cehd.umn.edu/artist/index.html
Suggestions for Topics that Might be Omitted from
Introductory Statistics Course
Courses
ourses
While there is an impressive growth in the number of students taking more advanced courses in
statistics, many of our students take only a single course in statistics. This has led to a tendency
to cram as much material into the syllabus as possible. The natural question then is what to
minimize or diminish. We offer these topics as candidates for reconsideration in the traditional
course.
Our guide for these suggestions is to keep in mind why the course is required for so many of our
students (and elected by so many others). We believe that students need to learn to think
scientifically and to deal with statistics in their own disciplines. Students should be able to read
research literature with a critical eye. They should be able to understand what was studied, what
was concluded, and how as (eventual) professionals and citizens they should judge the
conclusions in the context of their own discipline.
The goals set out in this document address concepts and methods that support the development
of such a student. Here are some thoughts on topics that might be reconsidered:
•
Probability theory. The original GAISE report recommended less emphasis on
probability in the introductory course and we continue to endorse that recommendation.
For many students, an introductory course may be the only statistics course that they
take; therefore some instructors will want to teach basic probability and rules about
23
•
•
•
•
random variables, with perhaps the binomial as a special case. However, the GAISE
goals and recommendations can be met without these topics.
Constructing plots by hand. Data displays are now made by computers. Students need to
know how to read and interpret them. Instead of spending lots of time creating
histograms by hand, use some of that time instead to develop a deeper understanding and
ask more challenging questions about what the plots tell us about the data.
Basic statistics. Histograms, pie charts, scatterplots, means, and medians are now taught
in middle and high school and are a prominent part of the Common Core State Standards
in Mathematics. Classes taught to adults continuing their education or to students with a
different high school background may need to spend a bit more time on basic statistics.
No matter the audience, instructors will want to be sure that students truly understand
these concepts, but should not dwell on them more than is necessary. Instructors may
want to briefly review them to be sure terminology and notation are consistent, but this
should take little time.
Drills with z-, t-, χ2, and F-tables. These skills are no longer necessary and do not reflect
modern statistical practice. Apps that perform the lookup (and are not limited to a finite
list of df values) are available in general purpose statistical software packages, web
pages, smartphones, or (soon) watches. Since statistical software produces a p-value as
part of performing a hypothesis test, a shift from finding p-values to interpreting p-values
in context is appropriate (see also the ASA statement on p-values: Wasserstein, R. L., and
Lazar, N. A., 2016). This shift makes it unnecessary to examine students on their ability
to use these tables, so they can usually be dispensed with on exams.
Advanced training on a statistical software program. SAS certification, non-introductory
R programming, and other more extensive programming topics belong in subsequent
courses. Modern students have grown up with computers and know how to search for
support online. The basic computer package skills needed to undertake analyses for the
introductory statistics course can often be taught throughout the course or developed
using online training. Some instructors may train students in using a specific software
package, but mastery of advanced programming skills should not be allowed to crowd out
data analysis skills or statistical thinking.
24
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[Monograph]. Retrieved from http://eric.ed.gov/.
Carver, R. and Stephens, M. (2014) “It is Time to Include Data Management in Introductory
Statistics”, In K. Makar, B. de Sousa, & R. Gould (Eds.), Sustainability in Statistics Education.
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Assessment,” Journal of Statistics Education, 10. Available at
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_Cobb.ppt.
Cobb, G. W. (2007), “The Introductory Statistics Course: A Ptolemaic Curriculum?” Technology
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(2007), Guidelines for Assessment and Instruction in Statistics Education (GAISE) Report: A
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Wenderoth, M.P. (2014), “Active Learning Increases Student Performance in Science,
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Garfield, J., delMas, R. and Zieffler, A. (2012), “Developing Statistical Modelers and Thinkers
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Horton, N.J. (2015), “Challenges and Opportunities for Statistics and Statistics Education:
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27
APPENDIX A:
A: Evolution of Introductory Statistics and
Emergence of Statistics Education Resources
Transformation of the Introductory Course
The modern introductory statistics course has roots that go back a long way, to early books about
statistical methods. R. A. Fisher’s Statistical Methods for Research Workers, which first
appeared in 1925, was aimed at practicing scientists. A dozen years later, the first edition of
George Snedecor’s Statistical Methods presented an expanded version of the same content, but
there was a shift in audience to prospective scientists who were still completing their degrees.
By 1961, with the publication of Probability with Statistical Applications by Fred Mosteller,
Robert Rourke, and George Thomas, statistics had begun to make its way into the broader
academic curriculum, but statistics still had to lean heavily on probability for its legitimacy.
During the late 1960s and early 1970s, John Tukey’s ideas of exploratory data analysis launched
the “data revolution” in the beginning statistics curriculum, freeing certain kinds of data analysis
from ties to probability-based models. Analysis of data began to acquire status as an
independent intellectual activity that did not require hours chained to a bulky mechanical
calculator. Computers later expanded the types of analysis that could be completed by learners.
Two influential books appeared in 1978: Statistics, by David Freedman, Robert Pisani, and
Roger Purves, and Statistics: Concepts and Controversies, by David S. Moore. These textbooks
were distinctive in focusing almost exclusively on statistical concepts rather than statistical
methods. They were aimed at a broad audience of consumers of statistical information rather
than for students who needed to learn to conduct statistical analyses. Then in the 1980s, more
and more introductory textbooks on statistical methods included a focus on concepts and real
data15.
The evolution of content has been paralleled by other trends. One of these is a striking and
sustained growth in enrollments. Statistics from three groups of students illustrate the growth:
•
•
At two-year colleges, according to the Conference Board of the Mathematical Sciences
(CBMS)16, statistics enrollments grew from 27% the size of calculus enrollments in 1970
to 74% in 2000 and exceeded calculus by 2010.
Also from the CBMS survey, enrollments in elementary statistics courses at four-year
institutions were up 56% in math departments and 50% in statistics departments from
2005 to 2010.
15
Cobb, G.W. (1987), “Introductory Textbooks: A Framework for Evaluation,” Journal of the American Statistical
Association, 82, 321-339.
16
http://www.ams.org/profession/data/cbms-survey/cbms-survey
28
•
The Advanced Placement exam in statistics was first offered in 1997 when 7,500 students
took it, more than in the first offering of an AP exam in any subject up to that time. More
than four times as many students were taking the exam by 2015 when nearly 200,000
students took the test17.
The democratization of introductory statistics has broadened and diversified the backgrounds,
interests, and motivations of those who take the course. Statistics is no longer reserved for future
scientists in narrow fields but is now a family of courses, taught to students at many levels, from
pre-high school to post-baccalaureate, with very diverse interests and goals. A teacher of today’s
beginning statistics courses can no longer assume that students are quantitatively skilled and
adequately motivated by their career plans.
Not only have the “what, why, who, and when” of introductory statistics been changing, but so
has the “how.” The last few decades have seen an extraordinary level of activity focused on how
students learn statistics and on how teachers can effectively help them learn.
Influential Documents on the Teaching of Statistics
As part of the Curriculum Action Project of the Mathematics Association of America (MAA),
George Cobb coordinated a focus group about important issues in statistics education. The 1992
report was published in the MAA volume Heeding the Call for Change18. It included the
following recommendations for teaching introductory courses:
Emphasize Statistical Thinking
Any introductory course should take as its main goal helping students to learn the basic
elements of statistical thinking. Many advanced courses would be improved by a more
explicit emphasis on those same basic elements, namely:
•
•
•
The need for data. The importance of data production.
The omnipresence of variability.
The quantification and explanation of variability.
More Data and Concepts, Less Theory and Fewer Recipes
Almost any course in statistics can be improved by more emphasis on data and
concepts, and less emphasis on theory and recipes. To the maximum extent feasible,
automate calculations and graphics.
Foster Active Learning
http://research.collegeboard.org/programs/ap/data/participation/ap-2015
Cobb, G.W. (1992), “Teaching Statistics,” in Heeding the Call for Change: Suggestions for Curricular Action
(MAA Notes No. 22), 3–43. Washington, D.C.: The Mathematical Association of America.
17
18
29
As a rule, teachers of statistics should rely much less on lecturing and much more on
alternatives such as projects, lab exercises, and group problem-solving and discussion
activities. Even within the traditional lecture setting, it is possible to get students more
actively involved.
The three recommendations were intended to apply quite broadly (e.g., whether or not a course
has a calculus prerequisite and regardless of the extent to which students are expected to learn
specific statistical methods). Cobb’s focus group evolved into the joint ASA/MAA Committee
on Undergraduate Statistics. A growing body of statistics educators were implementing the
recommendations and actively sharing their experiences with peers, often through projects and
workshops funded by the National Science Foundation (NSF).
In the late 1990s, Joan Garfield led an NSF-funded survey19 to explore the impact of this
educational reform movement. A large number of statistics instructors from mathematics and
statistics departments and a smaller number of statistics instructors from departments of
psychology, sociology, business, and economics were included. The responses were
encouraging: many reported increased use of technology, diversification of assessment methods,
and successful implementation of active learning strategies.
The American Statistical Association funded a strategic initiative to create a set of Guidelines for
Assessment and Instruction in Statistics Education (GAISE) at the outset of the 21st century.
This was a two-part project that resulted in the publication20 of A Pre-K–12 Curriculum
Framework21 and the original 2005 College Report that expanded upon the recommendations
from the Cobb Report to address technology and assessment. These two reports have had a
profound effect on the practice of teaching statistics and on the training of statistics educators at
all levels.
Since the GAISE publications, the widespread adoption of the Common Core State Standards22
has both strengthened the status of statistics as an academic necessity and challenged the content
of a first collegiate course in statistics. The arrival of students from high school already exposed
to topics formerly taught only in a college course (e.g., probability, exploratory data analysis,
measures of center and variability, basic ideas of inference) is a shift as profound as the 1970s
arrival of students without strong quantitative skills. New technology allowed the restructuring
of the 20th century curriculum to include focus on concepts rather than computation as an
adaptation to the new type of student. Forty years later, the 21st century curriculum has the
opportunity to build on a broader foundation of prior knowledge that leaves room to delve deeper
and farther than ever before possible.
Garfield, J. (2000), An Evaluation of the Impact of Statistics Reform: Final Report. National Science Foundation
(REC-9732404).
20
amstat.org/education/gaise
21
Franklin, C., Kader, G., Mewborn, D. S., Moreno, J., Peck, R., Perry, M., and Scheaffer, R. (2007), Guidelines for
Assessment and Instruction in Statistics Education (GAISE) Report: A Pre-K-12 Curriculum Framework,
Alexandria, VA: American Statistical Association.
22
http://www.corestandards.org/
19
30
The Emergence of Statistics Education Research and Resources
Even before the publication of the original GAISE College Report, distinctions between
mathematics education and statistics education were being made23. The connection between the
disciplines, however, remains important and interesting to both mathematicians and statisticians.
The American Statistical Association (ASA) maintains joint committees with the Mathematical
Association of America (MAA), the American Mathematical Association of Two-Year Colleges
(AMATYC), and the National Council of Teachers of Mathematics (NCTM).
The Statistical Education Section is one of the oldest sections within the ASA, founded in 1948,
originally focused on the education of professional statisticians. The current mission statement
of the Section includes advising the Association on educational elements in communication with
non-statistical audiences, promoting reach and practice in statistical education; supporting the
dissemination of development/funding opportunities, teaching resources, and research findings in
statistical education; and improving the pipeline from K-12 through colleges to statistics
professionals24.
The American Statistical Association recently updated their guidelines for undergraduate
programs in statistical science25, 26 to ensure that minors and majors in statistics provide
sufficient background in core skill areas: statistical methods and theory, data manipulation,
computation, mathematical foundations, and statistical practice.
In 2014 the ASA and MAA jointly endorsed a set of guidelines27 for those teaching an
introductory statistics course. These guidelines stipulate that instructors of statistics ideally meet
the following qualifications:
Experience with data and appropriate use of technology to support data analyses
Deep knowledge of statistics and appreciation for the differences between statistical
thinking and mathematical thinking
Understanding the ways statisticians work with real data and approach problems and
experiencing the joys of making discoveries using statistical reasoning
Mentoring by an experienced statistics instructor for instructors unfamiliar with the datadriven techniques used in modern introductory statistics courses
These guidelines recommend minimum qualifications for teaching introductory statistics as
consisting of the following:
Ben-Zvi, D., and Garfield, J. (2008), “Introducing the Emerging Discipline of Statistics Education,” School
Science & Mathematics, 108, 355-361.
24
http://community.amstat.org/statisticaleducationsection/home
25
http://www.amstat.org/education/curriculumguidelines.cfm
26
Horton NJ and Hardin J. “Teaching the Next Generation of Statistics Students to ‘Think with Data’: Special Issue
on Statistics and the Undergraduate Curriculum”, The American Statistician, 2015; 69(4):259-265,
http://www.tandfonline.com/doi/full/10.1080/00031305.2015.1094283.
27
http://magazine.amstat.org/blog/2014/04/01/asamaaguidelines/
23
31
two statistical methods courses, including content knowledge of data-collection methods,
study design, and statistical inference, and
experience with data analysis beyond material taught in the introductory class (e.g.,
advanced courses, projects, consulting, or research).
In 2000, the MAA founded a special interest group (SIGMAA) on Statistics Education. Their
purpose is also four-fold: facilitate the exchange of ideas about teaching statistics, the
undergraduate statistics curriculum, and other issues related to providing effective/engaging
encounters for students; foster increased understanding of statistics through publication; promote
the discipline of statistics among students; and work cooperatively with other organizations to
encourage effective teaching and learning28.
The AMATYC Committee on Statistics was founded in 2010 to provide a forum for the
exchange of ideas, the sharing of resources, and the discussion of issues of interest to the
statistics community. The committee strives to provide professional development opportunities
that support the teaching and learning of statistics and that foster the use of the GAISE College
Report recommendations in the first two years of college. It also serves as a liaison with faculty
at four-year institutions and with other professional organizations for the purpose of resource
sharing (see the AMATYC Statistics Resources Page29).
A 2006 charter established the Consortium for the Advancement of Undergraduate Statistics
Education (CAUSE) which had grown out of a 2002 strategic initiative within the ASA. The
mission of CAUSE is to support and advance undergraduate statistics education through
resources, professional development, outreach and research. CAUSEweb.org serves as a
repository for all of those areas. CAUSE also coordinates the US Conference on Teaching
Statistics (USCOTS) which has been held in the spring of odd-numbered years since 2005.
Since 2012, the electronic Conference on Teaching Statistics (eCOTS) has provided a virtual
conference experience on even-numbered years.
The oldest conference for statistics educators, however, is sponsored by the International
Association of Statistical Education (IASE)30, a section of the International Statistical Institute.
The International Conference on Teaching Statistics (ICOTS) has been held every four years
since 1982 at various global locations. The IASE also supports the Statistics Education
Research Journal (SERJ), a peer-reviewed electronic journal in publication since 2002.
Other refereed journals of interest to statistics educators include Teaching Statistics31, the
Journal of Statistics Education (JSE)32, and Technology Innovations in Statistics Education
(TISE)33.
28
http://sigmaa.maa.org/stat-ed/art1.html
http://www.amatyc.org/?page=StatsResources
30
http://iase-web.org/
31
http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1467-9639
32
http://www.amstat.org/publications/jse/
33
http://escholarship.org/uc/uclastat_cts_tise
29
32
33
APPENDIX B: Multivariable Thinking
The 2014 ASA guidelines for undergraduate programs in statistics recommend that students
obtain a clear understanding of principles of statistical design and tools to assess and account for
the possible impact of other measured and unmeasured confounding variables (ASA 2014)34. An
introductory statistics course cannot cover these topics in depth, but it is important to expose
students to them even in their first course (Meng 2011). Perhaps the best place to start is to
consider how a third variable can change our understanding of the relationship between two
variables.
In this appendix we describe simple examples where a third factor clouds the association
between two other variables. Simple approaches (such as stratification) can help to discern the
true associations. Stratification requires no advanced methods, nor even any inference, though
some instructors may incorporate other related concepts and approaches such as multiple
regression. These examples can help to introduce students to techniques for assessing
relationships between more than two variables.
Including one or more multivariable examples early in an introductory statistics course may help
to prepare students to deal with more than one or two variables at a time and examples of
observational (or "found") data that arise more commonly than results from randomized
comparisons.
Smoking in Whickham
A follow-up study of 1,314 people in Whickham, England characterized smoking status at
baseline, then mortality after 10 years (Appleton et al. 1996). The summary data are provided in
the following table:
SMOKER
No
Yes
Alive
502 (68.6%)
443 (76.1%)
Dead
230 (31.4%)
139 (23.9%)
We see that the risk of dying is lower for smokers than for non-smokers, since 31.4% of the nonsmokers died, but only 23.9% of the smokers did not survive over the ten year period. A
graphical representation using a mosaicplot (also known as an Eikosogram) represents the cell
probabilities as a function of area.
34
See also Wild's "On Locating Statistics in the World of Finding Out,” http://arxiv.org/abs/1507.05982.
34
We note that the majority of subjects have survived, but that the number of the smokers who are
still alive is greater than we would expect if there were no association between these variables.
What could explain this result?
Let's consider stratification by age of the participants (older vs. younger). The following table
and figure display the relationship between smoking and mortality over a 10-year period for two
groups: those age 18-64 and subjects that were 65 or older at baseline.
Baseline age
18-64
18-64
65+
65+
SMOKER
No
Yes
No
Yes
Alive
474 (87.9%)
437 (82.1%)
28 (14.5%)
6 (12.0%)
Dead
65 (12.1%)
95 (17.9%)
165 (85.5%)
44 (88.0%)
35
We see that mortality rates are low for the younger group, but the mortality rate is slightly higher
for smokers than non-smokers (17.9% for smokers vs 12.1% for the non-smokers).
Almost all of the participants who were 65 or older at baseline died during the follow-up period,
but the probability of dying was also slightly higher for smokers than non-smokers.
This example represents a classic example of Simpson's paradox (Simpson 1951; Norton and
Divine 2015). For all of the subjects, smoking appears to be "protective," but within each age
group smokers have a higher probability of dying than non-smokers.
How can this be happening? The following figure and table us to disentangle these relationships.
36
Not surprisingly, we see that mortality rates are highest for the oldest subjects.
We also observe that there is an association between age group and smoking status, as displayed
in the following figure and table.
Age roup
18-64
65+
Non-smoker
539 (50.3%)
193 (79.4%)
Smoker
532 (49.7%)
50 (20.6%)
Smoking is associated with age, with younger subjects more likely to have been smokers at
baseline.
What should we conclude? After controlling for age, smokers have a higher rate of mortality
than non-smokers in this study. This other factor is important when considering the association
between smoking and mortality.
37
Simple methods such as stratification can allow students to think beyond two dimensions and
reveal effects of confounding variables. Introducing this thought process early on helps students
easily transition to analyses involving multiple explanatory variables.
SAT Scores and Teacher Salaries
Consider an example where statewide data from the mid-1990s are used to assess the association
between average teacher salary in the state and average SAT (Scholastic Aptitude Test) scores
for students (Guber 1999; Horton 2015). These high stakes high school exams are sometimes
used as a proxy for educational quality.
The following figure displays the (unconditional) association between these variables. There is a
statistically significant negative relationship ( hat = -5.54 points, 0.001). The model
predicts that a state with an average salary that is one thousand dollars higher than another would
have SAT scores that are on average 5.54 points lower.
But the real story is hidden behind one of the "other factors" that we warn students about but do
not generally teach how to address! The proportion of students taking the SAT varies
dramatically between states, as do teacher salaries. In the Midwest and Plains states, where
teacher salaries tend to be lower, relatively few high school students take the SAT. Those that do
are typically the top students who are planning to attend college out of state, while many others
take the alternative standardized ACT test that is required for their state. For each of the three
groups of states defined by the fraction taking the SAT, the association is non-negative. The net
result is that the fraction taking the SAT is a confounding factor.
This problem is a continuous example of Simpson's paradox. Statistical thinking with an
appreciation of Simpson's paradox would alert a student to look for the hidden confounding
38
variables. To tackle this problem, students need to know that multivariable modeling exists but
not all aspects of how it can be utilized.
Within an introductory statistics course, the use of stratification by a potential confounder is easy
to implement. By splitting states up into groups based on the fraction of students taking the SAT
it is possible to account for this confounder and use bivariate methods to assess the relationship
for each of the groups.
The scatterplot in the next figure displays a grouping of states with 0-22% of students ("low
fraction," top line), 23-49% of students ("medium fraction," middle line), and 50-81% ("high
fraction," bottom line). The story is clear: there is a positive or flat relationship between teacher
salary and SAT score for each of these groups, but when we average over the groups, we observe
a negative relationship.
39
Further light is shed via a matrix of scatterplots (see the above figure): we see that the fraction of
students taking the SAT is negatively associated with the average statewide SAT scores and
positively associated with statewide teacher salary.
Recall that in a multiple regression model that controls for the fraction of students taking the
SAT variable, the sign of the slope parameter for teacher salary flips from negative to positive.
It's important to have students look for possible confounding factors when the relationship isn't
what they expect, but it is also important when the relationship is what is expected. It's not
always possible to stratify by factors (particularly if important confounders are not collected).
Multiple Regression
The most common multivariable model is a multiple regression. Regression can be introduced as
soon as students have seen scatterplots and thought about the patterns we look for in them. When
students have access to a statistics program on a computer, they can fit regression analyses
themselves. But even without computer access, they can learn about typical regression output.
The point is to show students a model involving three (or more) variables and discuss some of
the subtleties of such models. Here is one example.
Scottish hill races are scheduled throughout the year and throughout the country of Scotland
(http://www.scottishhillracing.co.uk). The official site gives the current records (in seconds) for
men and women in these races along with facts about each race including the distance covered
(in km) and the total amount of hill climbing (in meters). Naturally, both the distance and the
climb affect the record times. So a simple regression to predict time from either one would miss
an important aspect of the races.
For example, the simple regression of time versus climb for women's records looks like this:
40
Response variable is: Women's Record
R squared = 85.2%
R squared (adjusted) = 84.9%
s = 1126 with 70-2 = 68 degrees of freedom
Variable
Intercept
Climb
Coefficient
320.528
1.755
SE(Coeff)
222.2
0.088
t-ratio
1.44
19.8
P-value
0.1537
< 0.0001
We see that the time is greater, on average, by 1.76 seconds per meter of climb. The value of
85.2% assures us that the fit of the model is good with 85.2% of the variance in women's records
accounted for by a regression on the climb.
But surely that isn't all there is to these races. Longer races should take more time to run. And
although an of 0.852 is good, the model fails to account for almost 15% of the variance.
It is straightforward for students to learn that multiple regression models work the same way as
simple regression models but include two or more predictors. Statistics programs fit multiple
regressions in the same way as simple ones. Here is the regression with both Climb and
Distance as predictors:
Response variable is:
Women's Record
R squared = 97.5%
R squared (adjusted) = 97.4%
s = 468.0 with 70 - 3 = 67 degrees of freedom
Variable
Coefficient SE(Coeff)
t-ratio
Intercept
-497.656
102.8
-4.84
Distance
387.628
21.45
18.1
Climb
0.852
0.0621
13.7
P-value
< 0.0001
< 0.0001
< 0.0001
This regression model shows both the distance and the climb as predictors and has an of
0.975; a substantial improvement. More interestingly, the coefficient of Climb has changed from
1.76 to 0.85. That's because in a multiple regression, we interpret each coefficient as the effect of
its variable on y after allowing for the effects of the other predictors.
Closing Thoughts
Multivariable thinking is critical to make sense of the observational data around us.
This type of thinking might be introduced in stages:
1.
2.
3.
4.
5.
learn to identify observational studies,
explain why randomized assignment to treatment improves the situation,
learn to be wary of cause-and-effect conclusions from observational studies,
learn to consider potential confounding factors and explain why they might be confounding
factors, and
use simple approaches (such as stratification) to address confounding.
Multivariable models are necessary when we want to model many aspects of the world more
realistically. The real world is complex and can’t be described well by one or two variables. If
students do not have exposure to simple tools for disentangling complex relationships, they may
dismiss statistics as an old-school discipline only suitable for small sample inference of
randomized studies.
41
Simple examples are valuable for introducing concepts, but when we don't demonstrate realistic
models students are left with the impression that statistics is trivial and not really useful. This
report recommends that students be introduced to multivariable thinking, preferably early in the
introductory course and not as an afterthought at the end of the course.
References
Appleton, D. R., French, J. M., and Vanderpump, M.P. (1996), "Ignoring a Covariate: An
Example of Simpson's Paradox,” The American Statistician, 50, 340-341.
American Statistical Association (2014), 2014 Curriculum Guidelines for Undergraduate
Programs in Statistical Science, Alexandria, VA: Author. Available at
http://www.amstat.org/education/curriculumguidelines.cfm.
Guber, D. L. (1999), "Getting What You Pay for: The Debate over Equity in Public School
Expenditures,” Journal of Statistics Education, 7. Available online at
http://www.amstat.org/publications/jse/secure/v7n2/datasets.guber.cfm.
Horton, N.J. (2015), "Challenges and Opportunities for Statistics and Statistical Education:
Looking Back, Looking Forward,” The American Statistician, 69, 138–145.
Meng, X.L. (2011), "Statistics: Your Chance for Happiness (or Misery),” The Harvard
Undergraduate Research Journal, 2. Available at http://thurj.org/as/2011/01/1259.
Norton, H. J. and Divine, G. (2015), "Simpson's Paradox, and How to Avoid It,” Significance,
40-43.
Simpson, E. H. (1951), "The Interpretation of Interaction in Contingency Tables,” Journal of the
Royal Statistical Society, Series B, 13, 238-241.
42
APPENDIX C:
C: Activities, Projects, and Datasets
The GAISE College Report emphasizes the importance of students being actively engaged in
their own learning. Activities, projects, and interesting datasets can help instructors engage
students. In this appendix, we begin with a description of desirable characteristics of class
activities. We provide examples of activities that illustrate a simple two quantitative variable
data collection, a randomization test for the difference in two means, experimental design in a
matched pairs study, and multivariable thinking. We conclude with examples of datasets and
websites that house data.
Desirable Characteristics of Class Activities
In this appendix we focus on activities to be conducted in the classroom. Many of the desirable
characteristics described are also applicable to unsupervised activities conducted outside the
traditional classroom setting.
Structure and timing...
• Learning Goals – An activity should have clear and attainable learning goals. The
activity should build upon what students already know and lead students to discover or
explore a statistical concept. Ideally, activities completed early in the course become
scaffolding for concepts explored later in the course.
•
Self-Contained and Complete – An activity should include all the important statistical
concepts, necessary materials, and information from past class activities to complete the
activity in a timely fashion.
•
Beginning and Ending an Activity – The activity should begin with an overview and end
with a summary of what is being done and why. This should include connections that
build upon and extend statistical conceptual and methodological knowledge and
application, how the statistical analysis helps to answer questions specific to the context
of the activity, and what students are expected to learn from the activity.
Choosing data...
• Relevance – The activity should involve data about topics that interest students. Using
real data makes data relevant to a wide variety of student majors. If real data are not
used, then the activity should mimic a real-world situation. It should not seem like
“busywork” to students. For example, if you use coins or cards to conduct a binomial
experiment, explain real-world binomial experiments they could represent.
43
Note: Student interests vary such that a dataset that might be interesting and relevant for
one student may not be as interesting or relevant for another student. It is important to
use a variety of datasets that speak to students from diverse backgrounds, majors, and
interests. One way to gauge student interest is to give the class an option of what dataset
to work with in an activity. The choice could be made by student vote or even by using a
poll during the first week of class to judge the students’ interests and majors.
•
Contextual Background – Students should read and be asked questions about the
background that informs the context of the data. For example, if the data involves the
number of friends a person has on Facebook, then students should read a brief
background on some pertinent aspects about Facebook.
If the activity involves collecting/generating data...
• Design Decisions and Data Collection – Activities can include those that require class
input into design and data collection and those that are more prescriptive. It is desirable
that the class be involved in some of the decisions about how to conduct the activity
when time permits and when class learning objectives are advanced.
Note: When students are involved in construction and implementation of design and data
collection decisions, it is important that they invoke good design and data collection
principles taught in the class. For instance, when designing an experiment, students
should consider principles of good experimental design including randomization,
replication, controlling outside factors, etc., rather than “intuitively” deciding how to
conduct the experiment.
•
Human Subjects Review – Most classroom data collection activities are exempt from the
need for review by an Institutional Review Board (IRB). However, students should be
made aware of the importance of review when collecting data, especially data on human
subjects. Many students will work with an IRB in research methods courses in their own
disciplines.
Working in groups...
• Teamwork – Students can learn effectively from each other. While many students are
drawn to working in teams, whether formal or informal, some students may resist
working with peers. Because working effectively in teams is a highly valued skill in
government, industry, and academia that can be practiced in the classroom, instructors
should consider requiring some degree of teamwork in activities and projects.
Note: Appendix F on Learning Environments includes a discussion of the use of and
value of cooperative groups in the classroom.
•
The Role of Groups in Design Decisions – It is sometimes better to have students work in
teams to discuss how to design a statistical investigation and then reconvene the class to
44
discuss how it will be done, but it is sometimes better to have the class work together for
the initial design decisions. It depends on how difficult the issues to be discussed are and
whether each team will need to carry out data collection in exactly the same way.
Sharing activities...
• Resources for Activities – There are numerous sources for activities including the
Journal of Statistics Education (http://www.amstat.org/publications/jse/), STatistics
Education Web (http://www.amstat.org/education/stew/), the Consortium for
Undergraduate Statistics Education (http://www.causeweb.org) , and Teaching Statistics
(http://www.teachingstatistics.co.uk/).
• Sharing Activities with Other Instructors – For an activity to be easily usable and
modifiable, the following characteristics are desirable: (1) quick data collection with low
cost in time and resources, (2) available in a file format (such as Word) that makes
modification by the instructor easy, and (3) includes a sample answer key for instructors.
Final thoughts...
• In our experience, students enjoy seeing their own data amongst their classmates’ data.
Activities that collect non-sensitive data from students, either inside class or outside
class, perhaps through an online survey, provide this opportunity.
•
The activity should be substantive, compelling, and, when possible, fun!
This is a list of desirable characteristics of class activities. This does not imply that an activity
that does not meet every characteristic on this list is a poor activity. These characteristics are
items to consider when creating, adapting, or using an activity.
Example Activities/Datasets
In-Class Data Collection/Analysis Activities
EXAMPLE ACTIVITY 1: LEG LENGTH AND STRIDE LENGTH
(based on an activity used by John Gabrosek in his classroom)
Exploring bivariate relationships is an important part of an introductory statistics course. In this
activity, students investigate whether there is a relationship between the length of a person’s leg
and the number of steps required to walk a specified distance.
Materials Needed:
•
Tape Measures
45
Procedure:
•
•
•
•
Name
•
Split class into groups of 3 or 4 students
Have groups measure each student’s leg length from outside hip bone to floor
Simultaneously, have each student walk a specified route. Same route for each student. Instruct
students to silently count the number of steps they take as they walk the route.
Have students enter data into a simple data collection form
Sex
(M or F)
Leg Length (inches) –
measure right leg
Count of Steps
Compile class data and use to illustrate scatterplots, correlation, and regression. It is likely that the
relationship will be weak and negative.
Drink
Calcium
Diet Cola
48
Diet Cola
50
Diet Cola
55
Diet Cola
56
Diet Cola
58
Diet Cola
58
EXAMPLE ACTIVITY 2: RANDOMIZATION TEST FOR A DIFFERENCE IN MEANS - COLA
AND CALCIUM
Diet Cola
61
Diet Cola
62
(adapted from Larson, 2010 and Kahn and Laflamme 2015)
Setting: A study by Larson et al. (2010) examined the effect of diet cola
consumption on calcium levels in women. A sample of 16 healthy women aged
18-40 were randomly assigned (eight to each group) to drink 24 ounces of either
diet cola or water. Their urine was collected for three hours after ingestion of the
beverage and calcium excretion (in mg) was measured. The researchers were
investigating whether diet cola leaches calcium out of the system, which would
Water
45
Water
46
Water
46
Water
48
Water
48
Water 46
53
Water
53
Water
54
Instructor Notes:
• The weak relationship lends itself to a discussion of what other variables might
impact step count. Students usually identify that different people have different
gaits (though they are unlikely to use the term gait). Gait analysis can be used to
assess deviations from normal, especially if a person’s baseline gait has been
analyzed prior to an injury.
• A short distance (no more than a few hundred steps) is sufficient; data collection
takes about 5 minutes. Data entry can be done on the spot or by the teacher between
class sessions.
increase the amount of calcium in the urine for diet cola drinkers. Low calcium levels are
associated with increased risk of osteoporosis (Kahn and Laflamme 2015).
Results:
Diet Cola
mean
̅ 56.000
Water
mean: ̅ = 49.125
The difference in means is: ̅ − ̅ = 56.000 − 49.125 = 6.875.
Key Question: Does this difference (6.875) provide convincing evidence
that the mean amount of calcium excreted after drinking diet cola is higher
than after water OR could this difference be just due to random chance (in
assigning volunteers to the two groups)?
Approach: Simulate new samples generated by random chance and see how often we get a
difference as large as (or larger than) what was observed in the original sample (6.875). We will
do this first using a physical simulation (by hand), then switch to computer technology to
automate the process.
Physical Simulation
1. Start with a sheet of paper that has the 16 calcium amounts from the experiment (such as the table
above) and cut/tear the paper so that the numbers are separated from the diet cola/water groups and
each value is on its own slip of paper. [Instructor alternative: Put the 16 calcium amounts on
individual cards.]
2. Shuffle the slips/cards with calcium amounts and “deal” them randomly into two groups with 8 going
to the diet cola group and 8 going to the water group.
3. Find the mean for each group and the difference in the two means.
̅ = __________
(Diet cola)
̅ = __________
(Water)
̅ − ̅ = __________
(Difference)
Is this difference bigger than the 6.875 from the original sample? ____
4. Look at some of the other simulated differences from your classmates How many of them are bigger
than 6.875? [Instructor note: Perhaps draw a class dotplot of differences].
47
Simulation via technology
[Instructor note: Specific instructions below will depend on your technology. See the
technology notes below for several options including StatKey (http://lock5stat.com/statkey), a
Rossman/Chance applet (http://www.rossmanchance.com/applets), or the R package.]
5. Use technology to simulate the process you just did by hand – scrambling the 16 calcium values and
reassigning them to diet cola & water groups.
Which group got the smallest amount (45)?
Diet Cola
Water
Which group got the largest amount (62)?
Diet Cola
Water
6. Put the difference in means for your simulated sample in the table below, then repeat to generate four
more simulations and record the difference in means for each simulation.
Simulated
̅ − ̅ :
_____________ _____________ _____________ _____________
7. Now use the technology to generate a thousand or more simulations. Look at a dotplot (or histogram)
of the differences in means for all of these simulations. This is called a randomization distribution of
the differences and shows what we might expect to see if there really is no difference in calcium
excretion between the two groups.
Where is your randomization distribution centered? _____
Why does this make sense?
Does it look like the difference from the actual sample (6.875) is in an unusual place in your
randomization distribution?
8. To quantify the last question, we will estimate a p-value as the proportion of all those random chance
samples that have a difference in means as large as (or larger than) the original difference of 6.875.
Use technology to estimate the p-value for your randomization distribution.
What proportion of your randomization differences are 6.875 or larger?
p-value = ____________________
48
9. Interpretation: What does this p-value tell you about the "significance" of the difference in the original
sample? Does the difference look unusually large (indicating strong evidence that mean calcium
excretion tends to be higher after drinking diet cola) or does the difference look more typical of what
you would expect to see by random chance alone?
Instructor note: Here is a typical example (from StatKey) of a randomization distribution students might
produce in this activity:
Technology notes for the Randomization Activity:
We provide three different technology options (each freely available) for doing the randomizations needed for
parts 5-9 of the activity above.
StatKey (available at http://lock5stat.com/statkey)
•
•
•
•
•
From the main StatKey page, choose the Randomization “Test for Difference in Means.”
This dataset is already included in StatKey, so click on the drop down menu (labeled “Leniency and
Smiles,” just below the StatKey icon) to bring up a list of datasets and choose “Cola and Calcium
excretion.”
Check that the data and summary statistics shown in the “Original Sample” graph match the data for
this activity. Note: For data not already in StatKey, you can use the “Edit Data” button to copy/paste
or enter your own data.
Click on “Generate 1 Sample” to do a single randomization (Step 5 in the activity). The randomized
data is displayed and summarized in the bottom right and the difference in means is plotted in the
main dotplot at the left. Repeat this for several more randomizations (Step 6).
Click on the “Generate 1000 Samples” a few times to get a better picture of the randomization
distribution (Step 7).
49
•
To find what proportion of the randomizations gave differences as large as the original difference
(Step 9) choose the “Right Tail” option, click on the blue box that appears on the horizontal axis, and
change the endpoint to 6.875 (the difference in the original sample). The p-value is shown in the box
about the right tail.
RossmanChance Applet (available at http://www.rossmanchance.com/applets)
•
•
•
•
•
•
•
Under “Statistical Inference,” choose the option for “two means” (under “Randomization test for
quantitative response”).
You need to copy/paste or enter the data from the table in the activity above to replace the default data
in the applet. Also, the applet wants the group identifiers to be single words so delete the spaces to
change “Diet Cola” to “DietCola” for the first 8 cases.
Click on “Use Data” and check that the plot and summary statistics match the original sample.
Click the box next to “Show Shuffle Options” to bring up the controls for the randomizations.
Leave the number of Shuffles at 1 and click on ‘Shuffle Responses” to generate one randomization
(Step 5). The shuffled difference is shown below the summary statistics and plotted to the right.
Repeat for Step 6.
Change the number of shuffles to a larger number (like 3000) and “Shuffle Responses” again to
generate a histogram of the randomization distribution (Step 7).
To find what proportion of the randomizations gave differences as large as the original difference
(Step 9), fill in that value (6.875) in the box after “Count Samples” leaving the “Greater than ≥” alone.
Click on the “Count” button to see the count and proportion.
R (downloadable from http://www.r-project.org)
Here is an R script for creating the randomization differences and seeing what proportion are as extreme as the
6.875 difference in the original sample. It uses the nice do( ) function from the mosaic package to generate
repeated samples without needing a formal loop.
#Randomization test to compare two means
library(mosaic)
# Load the mosaic package
library(Lock5Data) # Load a package with the ColaCalcium dataset
data("ColaCalcium") # Load the dataset
mean(Calcium~Drink, data=ColaCalcium) #Compare means for two groups
#Compare means when the Drink values have been randomly permuted
mean(Calcium~shuffle(Drink), data=ColaCalcium)
#collect such simulated means for both groups for 2000 simulations
manymeans=do(2000) * mean(Calcium~shuffle(Drink), data=ColaCalcium)
head(manymeans)
#See some of what the do( ) function collects
#Find the difference in means for each simulation
randomdiffs=manymeans$Diet.cola - manymeans$Water
50
dotPlot(randomdiffs,width=0.1) #get a plot of the random differences
#find the proportion of simulations with differences as large as 6.875
sum(randomdiffs>=6.875)/2000
EXAMPLE ACTIVITY 3: COMPARING MANUAL DEXTERITY UNDER TWO CONDITIONS
(Adapted from Project 12.2, Utts and Heckard 2007)
Included in this activity description is
•
•
•
An Overview of the Activity
Suggestions for Design and Analysis
Project Team Form
Overview of Activity
These instructions are for the teacher. Instructions for students are on the “Project Team
Form.” (below)
Goal: Provide students with experience in designing, conducting and analyzing an experiment.
Supplies: (N = number of students, T = number of teams)
• T bowls filled with about 30 of each of two distinct colors of dried beans
• 2T empty paper cups or bowls
• T stop watches or watches with second hand
Instructor Note: A variation is to have students do the task both with and without wearing a
“surgical” or “food-service” glove instead of with the dominant and non-dominant hand. In that
case you will need N pairs of gloves.
The Story: A company has many workers whose job is to sort two types of small parts. Workers
are prone to get repetitive strain injury, so the company wonders if there would be a big loss in
productivity if the workers switch hands, sometimes using their dominant hand and sometimes
using their non-dominant hand. (Or, if you are using gloves, the story can be that for health
reasons they might want to require gloves.) Therefore, you are going to design, conduct, and
analyze an experiment making this comparison. Students will be timed to see how long it takes
to separate the two colors of beans by moving them from the bowl into the two paper cups, with
one color in each cup. (To add some context, you can state that each color bean represents an
automotive part of a slightly different size – for example, a front door bolt and a back door bolt.)
A comparison will be done after using dominant and non-dominant hands. (An alternative is to
51
time students for a fixed time, such as 30 seconds, and see how many beans can be moved in that
amount of time.)
Design and Analysis
Step 1: As a class, discuss how the experiment will be done. This could be done in teams first. See below
for suggestions.
1. What are the treatments? What are the experimental units?
2. Principles of experimental design to consider are as follows. Use as many of them as possible in designing
and conducting this experiment. Discuss why each one is used.
a. Blocking or creating matched-pairs
b. Randomization of treatments to experimental units, or randomization of order of treatments
c. Blinding or double blinding
d. Control group
e. Placebo
f. Learning effect or getting tired
3. What is the parameter of interest?
4. What type of analysis is appropriate – hypothesis test, confidence interval or both? What numerical and
graphical analyses are appropriate?
The class should decide that each student will complete the task once with each hand. Why is this preferable
to randomly assigning half of the class to use their dominant hand and the other half to use their non-dominant
hand? How will the order be decided? Should it be the same for all students? Will practice be allowed? Is it
possible to use a single or double blind procedure?
Note: Example 4 below deals with multivariable thinking in data analysis. Study design is an example of
multivariable thinking where different variables are controlled so that the relationship between variables of
interest can be isolated. For the bean sorting experiment, the matched pairs design controls for student-tostudent variability and randomizing the order of dominant/non-dominant hand controls for the learning effect.
Step 2: Divide into teams and carry out the experiment.
The Project Team Form shows one way to assign tasks to team members.
Step 3: Descriptive statistics and preparation for inference
Convene the class and create a plot of the differences. Discuss whether the necessary conditions for any
inferential analysis are met. Were there any outliers? If so, can they be explained? Compute the mean and
standard deviation for the differences.
Step 4: Inference
Have each team find a confidence interval for the mean difference and conduct the hypothesis test.
Step 5: Reconvene the class and discuss conclusions
52
Instructor Notes on Design:
•
On Step 1
a.
Blocking or creating matched-pairs - Each student should be used as a matched pair, doing the
task once with each hand.
b. Randomization of treatments to experimental units, or randomization of order of treatments Randomize the order of which hand to use for each student.
c. Blinding or double blinding - Obviously the student knows which hand is being used, but the
time-keeper doesn’t need to know.
d. Control group - Not relevant for this experiment.
e. Placebo - Not relevant for this experiment.
f. Learning effect or getting tired - There is likely to be a learning effect, so you may want to build
in a few practice rounds. Also, randomizing the order of the two hands for each student will help
with this.
• One possible design: Have each student flip a coin. Heads, start with dominant hand. Tails, start
with non-dominant hand. Time students to see how long it takes to separate the beans. The person
timing can be blinded to the condition by not watching.
Instructor Notes on Analysis:
•
What is the parameter of interest?
Define the random variable of interest for each person to be a "manual dexterity difference" of
d = number of extra seconds required with non-dominant hand
= time with non-dominant hand − time with dominant hand.
Define µd = population mean manual dexterity difference.
•
What are the null and alternative hypotheses?
H0 : µd = 0 and Ha: µd > 0 (faster with dominant hand)
To carry out the test, compute t = d − 0 then compare to the t-table or use technology to find the psd
n
value.
•
Is a confidence interval appropriate?
Yes, a confidence interval will provide information about how much faster workers can accomplish
s
the task with their dominant hands. The formula for the confidence interval is: d ± t * d , where t*
n
is from the t-table with df = n -1, and sd is the standard deviation of the difference scores.
Project Team Form
TEAM MEMBERS:
1. __________________________________
2. __________________________________
3. __________________________________
4. ___________________________
5. ___________________________
6. ___________________________
53
INSTRUCTIONS:
You will work in teams. Each team should take a bowl of beans and two empty cups. You are
each going to separate the beans by moving them from the bowl to the empty cups, with one
color to each cup. You will be timed to see how long it takes. You will each do this twice,
once with each hand, with order randomly determined.
1. Designate these jobs. You can trade jobs for each round if you wish.
Coordinator – runs the show.
Randomizer – flips a coin to determine which hand each person will start with, separately
for each person.
Time Keeper – must have watch with second hand or cell phone timer. Times each person
for the task.
Recorder – records the results in the table below.
2. Choose who will go first. The Randomizer tells the person which hand to use first. Each
person should complete the task once before moving to the 2nd hand for the first person.
That gives everyone a chance to rest between hands.
3. The Time Keeper times the person, while they move the beans one at a time from the bowl
to the cups, separating colors.
4. The Recorder notes the time and records it in the table below.
5. Repeat this for each team member.
6. Each person then goes a second time, with the hand not used the first time.
7. Calculate the difference for each person.
NAME:
Time for nondominant hand
Time for
dominant hand
d = difference
= non-dominant − dominant hand
RESULTS FOR THE CLASS:
Record the data here_________________________________________________________
Parameter to be tested and estimated is __________________________________________
Confidence interval__________________________________________________________
Hypothesis test – hypotheses and results__________________________________________
EXAMPLE ACTIVITY 4: MULTIVARIABLE THINKING IN THE ANALYSIS OF DIAMOND PRICING
(adapted from De Veaux, 2015)
54
Goal: Provide students with experience investigating a dataset where the relationship between
variables is conditional upon other variables. In this write-up, we use the R program and the
ggplot2 package to analyze the data. We place any graphs that students should create in the body
of the report. The same analysis could be done in SAS, SPSS or any other statistical software
program.
Data: This activity uses the diamonds dataset that is part of the ggplot2 R package
(http://www.inside-r.org/packages/cran/ggplot2/docs/diamonds). The dataset includes
information on 53,940 diamonds. There are ten variables measured on each diamond including
price (in U.S. Dollars), cut (quality of the cut), clarity (a measurement of how clear the diamond
is), color, and carat (weight from 0.2-5.01 carats). For a full description of the dataset open R
and then enter code: help(diamonds).
The Story: Diamond prices depend on the four C’s of a diamond; cut, clarity, color, carat. It is
pretty obvious that bigger diamonds cost more, or is it? In this activity you investigate the
relationship between cut and price of diamonds using a dataset that includes 53,940 diamonds.
Part 1: Univariate Analysis
1. Make an appropriate graph for each of the five variables; price, cut, clarity, color, and carat. For the
categorical variables, be sure that the categories are placed in a logical order from worst to best.
55
56
2. Describe any interesting features of the distribution of each variable.
Students should point out that: (1) price is unimodal, peak from $0-$1000 and very skewed right; (2)
carat is very choppy with a peak around 0.1-0.2 carats and then a smaller peak at around 1 carat and is
skewed right; (3) most diamonds are of at least very good cut; (4) color has large variability with
numerous diamonds of a lower color quality (left of G) and numerous diamonds of a higher color
quality; and, (5) relatively few diamonds are of very high clarity (far right side of graph).
Part 2: Bivariate Analysis – Your goal is to investigate the relationship between a diamond’s cut
and the price of the diamond.
3. Make an appropriate graph to investigate the relationship between price and cut. Describe what you
see. Is there anything surprising?
57
Students should point out that the median price for ideal cut diamonds is less than any of the
other cuts of diamonds. This does not make sense because ideal cut is the highest quality cut
possible.
Part 3: Multivariable Thinking
4. You should have noticed that ideal cut diamonds tend to have lower prices than any other cut. The
median price for ideal cut diamonds is $1810, while fair cut diamonds have median price $3282.
Brainstorm with a partner some ideas on why this might be true.
5. Now that you have brainstormed some ideas, let us see if the data can help us.
a.
First, make a scatterplot of price against carat. Describe what you see.
As expected there is a positive relationship between carat and price, with higher carat
generally associated with higher price.
b. Make an appropriate graph to investigate the relationship between carat and cut. Describe
how cut is related to carat.
58
Fair cut diamonds tend to be much larger than ideal cut diamonds. Basically, it is very
difficult to find a large diamond that can be cut as perfectly as necessary for an ideal cut
designation.
6. Now, let us look at only diamonds of size 1 carat.
a.
Below is a plot of price broken down by cut for these diamonds. What do you see?
For 1 carat diamonds, the price tends to increase as the cut quality improves. But, we have not
accounted for the other variables color and clarity.
b. Now let us take our 1 carat diamonds and only look at those of color = G or H and clarity = VS1
or VS2. There are 22 Fair, 53 Good, 64 Very Good, 82 Premium, and 27 Ideal diamonds meeting
these conditions. What do you see in the plot?
59
When you control for carat, color, and clarity, then, as expected, fair cut diamonds are
priced much less than ideal cut diamonds. The price of a diamond now seems to
follow the cut.
7. What does this activity tell you about investigating the relationship between two variables?
Note that this example and others like it are included in the STAT101 toolkit for instructors available at
http://community.amstat.org/stats101/home).
Examples of Naked, Realistic and Real data
One of the core recommendations of this report and its predecessor is to “Use real data.” The
next few small examples illustrate a continuum along a spectrum of “reality,” starting with data
having no context at all and progressing to data from an actual study designed to address a
question of interest in a particular field. The task at hand (fit a least squares line) is the same in
each case, and to help illustrate the distinctions, we have kept the number of data cases small in
each situation. In practice, electronic access to data and technology for doing graphics and
analysis frees us from restrictions of using such small datasets.
Naked data (not recommended)
Find the least squares line for the data below. Use it to predict Y when X=5.
X
1
2
3
4
6
8
Y
3
4
6
7
14
20
60
Critique: Made-up data with no context (not recommended). The exercise is purely
computational with no possibility of meaningful interpretation.
Realistic data (better, but not recommended)
The data below show the number of customers in each of six tables at a restaurant and the size of
the tip left at each table at the end of the meal. Use the data to find the least squares line
predicting the size of the tip from the number of diners at the table. Use your result to predict the
size of the tip at a table that has five diners.
Diners
1
2
3
4
6
8
Tip
$3
$4
$6
$7
$14
$20
Critique: A context has been added which makes the exercise slightly more appealing and shows
students a practical use of statistics. The actual data values are made-up and example feels
somewhat contrived.
Real data (better but not recommended)
The data below show the quiz scores (out of 20) and the grades on the midterm exam (out of
100) for a sample of eight students who took this course last semester. Use these data to find a
least squares line for predicting the midterm score from the quiz score.
Assuming that the quiz and midterm are of equal difficulty this semester and the same linear
relationship applies this year, what is the predicted score on the midterm for a student who got a
score of 17 on the quiz?
Quiz
20
15
13
18
18
20
14
16
Midterm
92
72
72
95
88
98
65
77
Critique: While data are from a real situation that should be of interest to students taking the
course, and the question asked may be relevant for the situation, the data do not provide a
compelling application of statistics.
Real Data, from a Real Study (preferable)
In a study of honeybees, Seeley (2010) observed that scout bees do a "waggle dance" to help
communicate the distance to a new nest site to bees back in the original nest. The table below
shows the distance to the new site (in meters) and duration of the dance (in seconds) recorded for
61
seven different scout honeybees. Use the data to find the least squares regression line and predict
the distance to a new nest when a honeybee dances for 1.5 seconds.
Duration (seconds)
0.40
0.45
0.95
1.30
2.00
3.10
4.10
Distance (meters)
200
250
500
950
1950
3500
4300
Critique: While the dataset is very small and only contains two variables (could there be other
factors at play?) the data arise from a real study (with reference) and address a real and
compelling research question.
Data (with Background and Stories) Available on the Web
EXAMPLE 1: AMES, IOWA REAL ESTATE DATA
The paper and dataset by DeCock (2011) describes sale of residential properties in Ames, Iowa
from 2006 to 2010. The dataset contains 2930 observations of home sales and 80 variables. The
data lends itself to a variety of analyses that can be done at the introductory statistics level
(regressing y = sales price on x = square footage is one example) and at a more advanced
modelling level.
While the paper does not contain a complete, ready-to-go activity, the author describes in detail
potential uses of the dataset. He provides helpful hints to employ and potential pitfalls to avoid
when using the dataset. It is quite easy to construct a simple activity that utilizes the data to
illustrate concepts in regression.
The dataset meets many of the desirable characteristics listed previously, including:
•
•
•
Data Relevance - The dataset is real data that represents actual real estate sales.
Contextual Background - Understanding contextual background is important to understanding the
data. Students need to be made aware of what different variables mean (the paper includes a
documentation file with detailed variable descriptions) to be able to realistically model sales prices.
Team Work - The richness of the dataset lends itself to use in a semester-long project that can best be
done in teams working together. This is especially true if teams are tasked with developing a best
regression model from the more than 70 potential predictor variables.
Teacher Hints:
1. The dataset is rich enough for many uses. In a regression modeling course students could be given the
dataset and asked to find an appropriate model to predict sales price. In an introductory statistics
course Sales Price can be summarized using basic numerical and graphical techniques. Pairs of
variables can be used to discuss correlation, two-way tables, etc.
2. The introductory statistics instructor may want to work with a smaller subset of the variables so as not
to overwhelm the students.
62
3. Instructors might use the Ames dataset and article as a template for collecting (or having students
collect) similar data from the local area.
Note: Appendix D on Technology includes a further discussion of the Ames, Iowa real estate
dataset.
EXAMPLE 2: U.S. ROAD LOCATION DATA
The paper by Stoudt et al. (2014) describes a lesson to randomly sample points in the continental
United States, determine whether or not each point is within one mile of a road, and use the
sample data to infer the proportion of the continental United States that is within one mile of a
road. The paper requires use of the R programming language and Internet access.
As with all papers published on the STEW website, the paper includes a complete, ready-to-go
activity.
The dataset meets many of the desirable characteristics listed previously, including:
•
•
•
Data Relevance - The dataset is real data collected in real-time by the students to answer a question of
importance to biologists, natural resource managers, and others concerned with providing habitat for
plants and animals.
Design and Data Collection – Students collect data to answer an important question. Using simple
tools available on the Internet students are able to quickly and accurately collect data to address the
question.
Team Work – The data collection allows for students to collect roughly 20 data points in a class
period. Students see that by pooling their data collection results they are rewarded with a more
precise interval estimate of the proportion of the U.S. within one mile of a road.
Teacher Hints:
1. Students use the latitude, longitude coordinates of a point to do two things: (i) determine
if the point falls within the continental U.S. and (ii) assuming the point is within the
continental U.S., determine whether or not the point is within one mile of a road.
2. Students will generate points that do not fall in the continental U.S. (points in the Pacific
Ocean, Atlantic Ocean, and Mexico are common). Because of this students will have
unequal sample sizes unless instructed to continue generating points until 20 are within
the continental U.S.
3. Students can edit their data file in Excel and then read back into R for the analysis if
desired.
Websites with Data
There are numerous websites that have freely available data. Data formats vary, but it is usually
simple to convert one of the datasets found at these sites to work with software available to the
63
instructor. The complexity of the data and the amount of processing (i.e., data cleaning) to get
the data ready for classroom use varies greatly. The list below provides a few places where an
instructor can get data.
•
•
•
•
•
•
•
Journal of Statistics Education (JSE) - http://www.tandfonline.com/loi/ujse20 The Data
Sets and Stories section of the journal includes data (often in several formats and a
documentation file explaining variable names).
Consortium for the Advancement of Undergraduate Statistics Education (CAUSE) https://www.causeweb.org/ The CAUSE website includes links to hundreds of locations
for data. On the Home page in the upper right corner type “Datasets” in the Search field.
New York City Open Data - https://data.cityofnewyork.us/ More than 1000 datasets on
various aspects of life in the Big Apple. You can search a specific term or click to view
all available datasets.
Winner data - http://www.stat.ufl.edu/~winner/datasets.html Larry Winner from the
Department of Statistics at the University of Florida has amassed hundreds of datasets.
Each dataset includes a description.
OzDASL - http://www.statsci.org/data/multiple.html Datasets categorized by statistical
topic.
Revolution Analytics R Data - http://mran.revolutionanalytics.com/documents/data/
Links to various data sources.
Kaggle - https://www.kaggle.com/ Website that hosts data analysis competitions. Many
datasets here are quite large and very messy. Establishing a free account is necessary for
access to the data.
Note: Appendix D on Technology includes other sources of data available on the web.
An additional source of data is from published papers. You can contact the author and journal
asking for permission to use a dataset in teaching. Many authors and journals will grant
permission for educational purposes and provide you with the dataset.
References
DeCock, D. (2011), “Ames, Iowa: Alternative to the Boston Housing Data as an End of Semester
Regression Project,” Journal of Statistics Education, 19. Available at
http://www.amstat.org/publications/jse/v19n3/decock.pdf
De Veaux, Dick (2015) “What Makes Diamonds so Expensive?” Stats 101 Public Library.
Available at
http://community.amstat.org/HigherLogic/System/DownloadDocumentFile.ashx?DocumentFile
Key=b13124e7-09aa-a775-fb51-6639d1d457ca&forceDialog=0
64
Kahn, A. and Laflamme, M. R. (2015), “Calcium Deficiency Disease,” Heathline. Available at
www.healthline.com/health/calcium-deficiency-disease.
Larson, N. S., Amin, R., Olsen, C., and Poth, M. A. (2010), “Effect of Diet Cola on Urine
Calcium Excretion,” Endocrine Reviews – Endo 2010 Abstracts, 31, S1070.
Seeley, T. (2010), Honeybee Democracy, Princeton University Press, Princeton, NJ, p. 128.
Stoudt, S., Cao, Y., Udwin, D., and Horton, N. J. (2014), “What Percent of the Continental US is
Within One Mile of a Road?” STatistics Education Web. Available at
http://www.amstat.org/education/stew/pdfs/PercentWithinMileofRoad.pdf
Utts, J. and Heckard, R. (2007), Mind on Statistics – Instructor’s Resource Manual, Duxbury
Press, Belmont, CA.
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APPENDIX D: Examples of Using Technology
This appendix introduces different forms of technology that can be used to fulfill the GAISE
recommendation to “Use technology to explore concepts and analyze data.” Additionally, these
forms of technology can help us to achieve some of the other GAISE College Report
recommendations, such as stressing conceptual understanding, gathering and using real data, and
fostering active learning.
Because technology changes so quickly and access to forms of technology varies from instructor
to instructor, we will be highlighting how certain methods can be used to meet the
recommendation; specific guidelines for particular brands or forms of technology will be
avoided. A special effort has been made to keep the material current and relevant in light of
constant advancements in technology.
When considering the use of technology in the classroom, the instructor should first start with the
learning goal or learning objective and then carefully consider what forms of technology could
be used to best meet that goal or objective. Next, the students in the classroom must be
considered. What form of technology would students learn most quickly (if needed)? How
much training would be necessary to allow students to seamlessly engage with the technology? It
is important to pick technology that does not become an additional burden for students or that
hinders them further from meeting goals or objectives.
In this appendix, we will focus on the following:
1.
2.
3.
4.
5.
Interactive Applets
Statistical Software
Accessing Real Data online (Observational, Experimental, Survey)
Using Games and Other Virtual Environments
Real Time Response Systems
Using Interactive Applets
Interactive applets can be used to emphasize important statistical concepts without being
encumbered by lots of calculations. 35 It’s important to note, however, that free applets vary
widely in terms of support, maintenance, and compatibility with evolving technology platforms.
We recommend that instructors test applets on classroom systems each time they plan to use
them in the classroom.
Applets are available that focus on a wide array of topics. To list just a few, there are applets that
are available for using randomization and bootstrap techniques to conduct inference, for
35
There are many places on the web that house statistical applets, and an internet search on a statistical concept can
often generate a few openly available applets. Often times, applets are also available with certain textbooks.
66
discussing sampling distributions of the sample proportion and the sample mean, and for
demonstrating the concept of “confidence” with confidence intervals. Additional applets can help
students recognize the effect of outliers on the simple linear regression equation as well as the
effect of outliers on the values of measures of center and variability. There are also applets that
can simulate probabilities taken over the long run.
Applets can be used in many ways. As an example, applets can be the focus of a class
demonstration, or they can be used by students as part of a homework assignment, a computer
lab activity, a class project, a quiz, or an exam. Applets can used by a single student at a time, as
a team/partner activity, or by the whole class at once.
Best Practices and Ideas found in Statistics Education Literature
•
Applets work well with the query first method. This means that the students try to answer
the conceptual questions first on their own and then again after using the applet.
o To see more information, see the following article:
delMas, R., Garfield, J., and Chance, B. (1999), “A Model of Classroom
Research in Action: Developing Simulation Activities to Improve Students’
Statistical Reasoning,” Journal of Statistical Education, 7. Available at
http://www.amstat.org/publications/JSE/secure/v7n3/delmas.cfm.
•
In the case of an applet that uses the concept of repeated sampling for randomization tests
or bootstrapping techniques, first sample one at a time, and then stop to explain what is
being illustrated. You may need to take another sample and explain the process again.
After the students appear to understand, you can then increase the number of samples to
1000 or a higher value.
o For an example of this process, see the following article:
Lock Morgan, K., Lock, R., Lock, P.F., Lock, E., and Lock, D. (2014), “StatKey:
Online Tools for Bootstrap Intervals and Randomization Tests,” ICOTS9
Proceedings [online]. Available at http://iaseweb.org/icots/9/proceedings/pdfs/ICOTS9_9B2_LOCKMORGAN.pdf
•
Pick applets that make it easier to focus on the concepts and to help introductory students
experience the entire investigative process. For example, the simulation should be similar
to a physical method students could use to illustrate a concept, for example, by using
cards or coins. Additionally, the simulation should allow for easy transition to multiple
types of inference (e.g., from inference about difference between two independent
proportions to difference between two independent means).
o To see more about this and how simulation-based inference is changing the
modern curriculum, see the following articles:
Rossman, A., and Chance, B. (2014), “Using Simulation-based Inference for
Learning Introductory Statistics,” WIREs Computational Stat, 6, 211-221.
o Tintle, N., Chance, B., Cobb, G., Roy, S., Swanson, T., and VanderStoep, J.
(2015), “Combating Anti-statistical Thinking using Simulation-based Methods
67
through the Undergraduate Curriculum,” The American Statistician, 69(4), 362370.
Future Direction of Applets and Interactive Visualizations
In the past, the statistics education community has mostly relied on a handful of people and
organizations to provide applets to help students build conceptual understanding. However, it is
becoming easier and easier to design one’s own statistical applets and other interactive
visualizations, and soon, instructors will be able to use readily available open software to create
their own public interactive visualizations. For example, Shiny, a web application framework for
R, allows the user to turn displays and analysis into interactive web applications (some level of
familiarity with R is needed).
•
•
•
For an overview of using R and Shiny in the classroom, see Doi, J., Potter, G., Wong, J.,
Alcaraz, I., and Chi, P. (2016), “Web Application Teaching Tools for Statistics using R
and Shiny,” Technology Innovations in Statistics Education 9(1), available at
http://escholarship.org/uc/item/00d4q8cp
To see examples of some interactive visualizations: see http://shiny.rstudio.com/gallery/
For more information about writing code for these visualizations: see http://www.rbloggers.com/interactive-visualizations-with-r-a-minireview/
Even instructors who do not have the time or desire to create their own visualizations might find
the list of example visualizations under the Shiny gallery a way to bridge some of the gap
between what students may traditionally see in an introductory course and the real data they may
see outside of the classroom (e.g., movie reviews, airline data, bus route data, etc.).
•
For further discussion of data for the modern student, see the following article:
Gould, R., (2010), “Statistics and the Modern Student,” International Statistical Review,
78, 297–315.
EXAMPLE 1: USING STATISTICAL APPLETS TO PERFORM RANDOMIZATION AND BOOTSTRAPPING TECHNIQUES
Since the first GAISE College Report, more and more introductory courses have been
incorporating randomization and bootstrapping techniques into the curriculum, and one way in
which these techniques can be incorporated into a course is by using statistical applets36. To see
an example of this type of activity, please see Appendix C in this report.
EXAMPLE 2: CREATING A STORY BOARD, VIDEO OR CARTOON ABOUT FINDINGS FROM AN APPLET
The following is a sample handout that can be used or modified in conjunction with an activity
involving the use of an applet.
Student Handout
36
Two free websites that can be used to do this are the Rossman and Chance website
(http://www.rossmanchance.com/applets/) as well as the Lock 5 website
(http://www.lock5stat.com/statkey/index.html). Some statistical software packages do this as well, such as
Statcrunch, R and JMP.
68
In class, we have been talking about confidence intervals for the population mean. What does
the term “confidence” mean? A link to an applet about confidence intervals has been provided
by your instructor. With your teammates, explore the applet and determine what it is trying to
demonstrate.
You should be able to answer the following three questions:
1.) If you were to take 100 different random samples and construct 100 95% confidence
intervals for the population mean, would each of the intervals be exactly the same -having exactly the same upper and lower bound? Explain your reasoning. Why would
or wouldn’t they be the same?
2.) For these intervals, what do we know about the population mean in relation to those
100 confidence intervals?
3.) What does it mean to be 95% confident?
Now that you understand the simulation, do one of the following activities:
• Create a script for a two-minute educational video that explains what is happening in
the applet. The audience of the educational video should be people who have not taken
a statistics course.
• Imagine that you have been given the opportunity to create a cartoon about statistics
for the college newspaper. Create a cartoon demonstrating the concept of “confidence.”
• Create a quick two minute video using a free online recording program37 that explains
what is being demonstrated in the applet.
Inspiration:
Fewster, R. (2014), “Teaching Statistics to Real People: Adventures in Social
Stochastics,” ICOTS 9 Proceedings. Available at http://iaseweb.org/icots/9/proceedings/pdfs/ICOTS9_PL3_FEWSTER.pdf .
Turner, S., and Dabney, A. (2015), “A Story Based Simulation for Teaching Sampling
Distributions,” Teaching Statistics, 37, 23-25.
Teaching Note:
It’s important to think carefully about how long students should spend on this task. You
might want to give them a timeline of one class period so they can focus more on the
statistical concepts and less, for example, on perfecting a two-minute recording.
EXAMPLE 3: EXPLORING MISCONCEPTIONS ABOUT SAMPLING DISTRIBUTIONS BY USING AN APPLET
Here is an example student handout that can be used or modified in conjunction with an applet
that demonstrates the sampling distribution.
37
For example, Jing! (www.techsmith.com/jing.html) or Screencast-O-Matic (www.screencast-o-matic.com).
69
Student Handout
Before using the applet, answer the following questions. For these questions, write down what
you think is the best answer. Please write these down in pen, so that you can’t change these
answers. As you complete this activity you might find out that these ideas have been confirmed
or are incorrect, that is okay. If they are incorrect, it is important to see why they are incorrect
and to identify them correctly later on. Seeing mistakes and misconceptions is important so that
you remember them later on.
PART ONE
Sketch the graph of each of these.
Normal
Sampling Distribution of
the sample mean with n =
10, where the original
population was Normal
1.)
2.)
3.)
4.)
Sampling Distribution of
the sample mean with n =
100 where the original
population was Normal
Describe the centers of the distributions. Are they the same? Different? In what way?
Describe the variability of the distributions. Are they the same? Different? In what way?
Describe the shape of the distributions. Are they the same? Different? In what way?
Very briefly explain your thinking: Why do you anticipate these specific descriptions?
Sketch the graph of each of these.
Right Skewed
Sampling Distribution of
the sample mean with n =
10, where the original
population was Right
Skewed
Sampling Distribution of
the sample mean with n =
100 where the original
population was Right
Skewed
70
1.)
2.)
3.)
4.)
Describe the centers of the distributions. Are they the same? Different? In what way?
Describe the variability of the distributions. Are they the same? Different? In what way?
Describe the shape of the distributions. Are they the same? Different? In what way?
Very briefly explain your thinking: Why do you anticipate these specific descriptions?
Sketch the graph of each of these.
Uniform
1.)
2.)
3.)
4.)
Sampling Distribution of
the sample mean with n =
10, where the original
population was Uniform
Sampling Distribution of
the sample mean with n =
100 where the original
population was Uniform
Describe the centers of the distributions. Are they the same? Different? In what way?
Describe the variability of the distributions. Are they the same? Different? In what way?
Describe the shape of the distributions. Are they the same? Different? In what way?
Very briefly explain your thinking: Why do you anticipate these specific descriptions?
PART TWO
Now go to the interactive applet website38 given to you by your instructor. Complete the table
below.
Shape
Mean
Standard
deviation
38
There are many options for applets that may work. Some textbook publishers include applets with their textbooks.
Applets can also be found within some statistical packages like StatCrunch or even openly available on the internet.
Since instructor resources will vary and websites change rapidly, specific websites are not given here. When
choosing an applet, make sure that you pick an applet that allows students to easily change the sample size and the
population distribution. It should also allow the instructor to show the results one sample at a time, a few samples at
a time, and then many samples at a time.
71
Normal Distribution
Sampling Distribution of the
sample mean with n = 10
where the original
population was Normal.
Sampling Distribution of the
sample mean with n = 100
where the original
population was Normal
1.) Describe the centers of the distributions. Are they the same? Different? In what way?
2.) Describe the variability of the distributions. Are they the same? Different? In what way?
3.) Describe the shape of the distributions. Are they the same? Different? In what way?
Complete the table below.
Shape
Mean
Standard
deviation
Right Skewed Distribution
Sampling Distribution of the
72
sample mean with n = 10
where the original
population was Right
Skewed
Sampling Distribution of the
sample mean with n = 100
where the original
population was Right
Skewed
1.) Describe the centers of the distributions. Are they the same? Different? In what way?
2.) Describe the variability of the distributions. Are they the same? Different? In what way?
3.) Describe the shape of the distributions. Are they the same? Different? In what way?
Complete the table below.
Shape
Mean
Standard
deviation
Uniform Distribution
Sampling Distribution of the
sample mean with n = 10
where the original
population was Uniform.
73
Sampling Distribution of the
sample mean with n = 100
where the original
population was Uniform.
1.) Describe the centers of the distributions. Are they the same? Different? In what way?
2.) Describe the variability of the distributions. Are they the same? Different? In what way?
3.) Describe the shape of the distributions. Are they the same? Different? In what way?
REFLECTIONS
Where did you see that you were initially correct?
Where did you see that you were initially incorrect?
What did you learn during this experience about what happens to the sampling distribution of the
sample mean as n increases?
‘
Inspiration:
delMas, R., Garfield, J., and Chance, B. (1999), “A Model of Classroom Research in
Action: Developing Simulation Activities to Improve Students’ Statistical Reasoning,”
Journal of Statistical Education, 7. Available at
http://www.amstat.org/publications/jse/secure/v7n3/delmas.cfm.
Teaching Notes:
•
It is important that students understand they don’t have to be correct on the first attempt.
They should do their best to think about the issues involved, but they are not required to
be correct. In fact, if they discover a misconception, it gives them something to write
about in the reflection part of the experience. During the lab activity, the instructor should
walk around the room and help students discover their own misconceptions. Perhaps even
a few students can share their misconceptions so that other students might realize they
also had those misconceptions.
74
•
It is helpful if you give out this activity in two parts. First, give out part one and have
students complete it in pen; then, give out part two. It is also helpful, when possible, if
part one and part two can be copied onto different colored sheets of paper.
Teaching Concepts and Analyzing Data with Statistical Software
It is self-evident that statistical software can eliminate or reduce the computational burdens in a
statistics course, especially when using large real data sets. One of the key advantages of
incorporating a package like SPSS, Minitab, JMP, R, StatCrunch, Stata, any of the many Excel
add-ins, or on-line tools into the course is that they can relieve both students and teachers of the
drudgery of computational tasks. Software can considerably reduce the amount of class and
homework time devoted to calculation, and can free up cognitive and time resources for other
ends. Most introductory-level textbooks now include examples and/or instruction in the use of
software and provide datasets to accompany the text. Statistical software allows us to easily
show an example data set with thousands of observations and explore a potential multivariate
relationship within that data set. Other examples that involve having students perform common
analytical tasks and explore data using statistical software can be found in Appendix C.
Using Statistical Software to Teach Concepts
Educators who view a statistical package only as a computational engine may want to consider
the considerable potential of these packages for helping students build deep understanding of
fundamental abstract concepts. The statistics education literature contains numerous articles that
both advocate for, and demonstrate the efficacy of, using software to improve student learning
(Chance et al. 2007; West 2009). Software simplifies and expedites the process of constructing
and modifying graphs and also allows for replicating operations. For example, in the past, we
might have been reluctant to ask students to make multiple histograms of the same data to
illustrate the effects of bin width. With software, the task becomes easy. As such, software
affords instructors the chance to create in-class demonstrations and homework assignments that
guide learners to the “aha! moment” – that moment when a concept is no longer a technical
textbook definition but an insight the student genuinely owns. One common example is the
concept of a distribution. By using software to make dotplots, boxplots and histograms to
visualize how individual data points vary along a number line, students gradually construct the
idea that observations spread out across a certain range, while also concentrating in certain
regions.
For a more subtle example, consider sampling variability among simple random samples. This
is a concept that is particularly elusive for many students, even for those with considerable prior
exposure. Students may read lucid explanations, hear a clear lecture, view or interact with a
Central Limit Theorem applet, and yet still not really be able to write or speak confidently about
sampling variability or sampling error. Students often have trouble reconciling the images of
75
“all possible samples” with the knowledge that we typically draw a single random sample.
Software may provide an additional avenue to build understanding.
EXAMPLE ACTIVITY
To use this activity in class, students need to have access to computers with the school’s favored
statistical package available. In classes where this is not feasible, the activity can be modified to
be a homework assignment to be completed before class. As suggested elsewhere in this report,
if technology is not available to support a homework assignment, instructors might still
demonstrate software in class or share images of relevant software output.
Select a set of microdata from a population, such as live births in the United States for one month
(full years available for download as a text file at
http://www.cdc.gov/nchs/data_access/vitalstatsonline.htm#Births). The entire dataset contains
nearly four million rows, exceeding the limits of Excel and Notepad (among other programs), so
it requires some instructor pre-work. It may be wise to select a single month to provide the class
with a smaller, but still quite large, table of data. Choose one continuous variable, such as
birthweight. Have each individual student open the data set within the software, and explain to
the class that this really is population data: every child born in the U.S. for that period. The
purpose of this demonstration is to explore the extent to which simple random sampling reliably
produces “good” estimates of various population parameters. For example, we might consider
the mean, median, and standard deviation.
The instructor uses her/his computer to find the parameters of the population. For dramatic
effect, one might even write them on the board and then conceal them, as a metaphor for the true
but unknown parameter.
Then, in the first stage, each student uses the software to select a random sample of, perhaps n =
50 rows of data, and saves this subset as the student’s personal, single random sample. Indicate
to the class that each student is a separate, independent investigator gleaning information from a
large population. In a small class, students might take multiple samples to achieve the desired
result.
The instructor would then ask each student to use the software to find the sample mean and
construct both a 95% and a 90% confidence interval for the mean of the population.
Once the students have constructed their confidence intervals, they would be reminded of the
value of the actual population mean. The instructor could then say, “First look at your 95%
confidence interval, and see if it contains/brackets the actual value of µ. Remember, ordinarily
we don’t know mu, and our only knowledge about the population would come from our one
sample. If your only knowledge of this population had been your sample, how many of you
would have ‘missed’ µ?”
Students could be asked to stand in place and count off. Naturally, this should be roughly 5% of
the class.
76
Once the students are seated, the instructor could conduct a very brief discussion to inquire why
their results were “wrong,” leading to the conclusion that sampling error is inherent in the
practice of random sampling, rather than any kind of mistake by the investigator.
While these students remain standing, the instructor could ask the same question again, this time
referencing the 90% interval, and ask unlucky students to stand. The instructor could point out to
the class that (a) the same students are standing again, but (b) they are now joined by an
approximately equal number.
Depending on time and the type of software, one might also construct confidence intervals for
the median and standard deviation.
If students do not have software in class, one might simply have them take the random samples
and construct CIs for homework, bringing their results to class and/or submitting the results
online prior to class. At that point, the instructor could create a graph summarizing the
distribution of sample means and sample 95% and 90% confidence intervals.
Inspiration:
Centers for Disease Control and Prevention, National Center for Health Statistics (2016),
“Vital Statistics Data Available Online.” Available at
http://www.cdc.gov/nchs/data_access/vitalstatsonline.htm#Births
Chance, B., Ben-Zvi, D., Garfield, J., and Medina, E. (2007), “The Role of Technology in
Improving Student Learning of Statistics,” Technology Innovation in Statistics
Education, 1. Available at http://escholarship.org/uc/item/8sd2t4rr.
Diez, D.M., Barr, C.D., and Cetinkaya-Rundel, M. (2012), OpenIntro Stats (2nd Ed.).
Available at https://www.openintro.org/stat/textbook.php?stat_book=os.
Scheaffer, R., Gnanadesikan, M., Watkins, A., and Witmer, J. (1996), Activity-Based
Statistics: Instructor Resources. New York: Springer Verlag.
West, W. (2009), “Social Data Analysis with StatCrunch: Potential Benefits to Statistical
Education,” Technology Innovations in Statistics Education, 3. Available at
http://escholarship.org/uc/item/67j8j18s.
Using Software to Create a Wider Variety of Visualizations
Software not only facilitates the creation and manipulation of traditional statistical graphs, it has
also introduced new methods of visualizing large data sets in ways that can stimulate insight and
curiosity among undergraduates (and their teachers). Through the use of interactive controls and
visual primitives like color, shape, and size, a user can quickly learn to create, modify, or
manipulate multidimensional graphics. Such graphing tools are engaging and fun, and they invite
the kind of exploration that lies at the heart of statistical thinking.
77
One innovative graph type is the bubble chart, which might be thought of as a super-charged
scatterplot. In a bubble plot, there are two quantitative variables on the X and Y axes.
Additionally, by replacing dots with “bubbles” of varying sizes and colors, one can represent two
additional categorical or quantitative variables. Finally, one can include a time dimension and
animate the scatterplot.
As a first illustration, visit the http://www.gapminder.org/world to see a vivid interactive fivedimensional graph that is interactive and animated (see image below). At the same site, one can
download the data (originally from the World Bank’s World Development Indicators) and the
software needed to create the graph.
In the default graph as shown, we have data from more than 200 countries covering the period
from 1800 through 2013. The vertical axis is Life Expectancy at Birth (in years) and the
horizontal axis is the log of Income per Person (GDP per capita, in inflation-adjusted purchasingpower parity in US dollars). Bubble areas correspond to the population of each country annually,
and the bubble colors indicate the region of the world for each country.
By pressing the Play button, one sets the graph into motion, tracing the changes in the variables
starting in 1800 and progressing through 2013. As the animation continues, patterns and
deviations from those patterns appear quite vividly. For example, in the years from roughly 1913
through 1919, life expectancy in much of the world plummets and then rebounds; this time
period corresponds to World War I and the Spanish flu epidemic. In our classroom experience,
students recognize the dramatic shift in the numbers and raise questions about it. In other words,
78
students engage in statistical thinking as a consequence of viewing this particular visualization.
Moreover, one does not need extensive instruction in how to interpret such a graph.
Mapping is another increasingly common visualization that is intuitive and insight-provoking,
though statistics textbooks have been slow to add maps to the canon of basic statistical graphing.
The Gapminder site includes a world map, as do some other software packages. For this
illustration, we’ll look at the mapping feature that is standard in JMP, along with a dataset that
ships with JMP. This example does not provide complete step by step instructions, but merely
illustrates the capability of the software.
JMP’s “World Demographics” data set contains observations of 32 variables for 238 countries of
the world in 2009. After opening the data table, the user invokes JMP’s Graph Builder platform
which presents a list of available variables and a blank “canvas” for graph creation. To make a
map, one selects a geographic identifier variable and another variable to determine a color
gradient. Below is a world map showing the 2009 life expectancy at birth, by country.
Student users can create this graph in a few steps with a point-and-click interface, and can
explore different variables in similar fashion. Here again, both the construction and the
interpretation of the visualization can occur with minimal instruction—in contrast to, for
example, a histogram or box-and-whiskers plot of the same data. Given their visual impact,
simple maps like this provide an excellent opportunity to tell a story from data, a key goal of
undergraduate statistics education.
79
Inspiration:
JMP Software, Sample Data Files.
Rosling, Hans. Gapminder World. Accessed June 9, 2015 at www.gapminder.org/world.
Using Software for Reproducibility and Better, Clearer Student Assignments
One recent trend in the scientific community is an emerging consensus on the value and
importance of reproducibility in scientific publications (see, for example, the editorial in Nature,
2014). In 2014, at a gathering convened by the US National Institutes of Health and the journals
Nature and Science, attendees adopted a set of guidelines calling for, among other provisions,
publication of statistical procedures, method of randomization and other detailed information to
allow for others to reproduce the published work.
In a statistics classroom, instructors may seek reproducibility as well; in addition to asking
students to report final results of an analysis, we may also wish to see the code or dialog choices
that generated the output, as well as reading the conclusions that student authors drew. Here
again, technology can simplify and expedite the process.
One freely available tool is R Markdown. For this example, we’ll demonstrate the ease of use
and the instructional benefits of using R Markdown as implemented in RStudio. In this example,
we use the Old Faithful dataset to illustrate how the R Markdown environment integrates a
student’s code with output and with whatever commentary or responses a student might add. Full
instructions are beyond the scope of this example; we include it to indicate how this particular
technology can overcome a common obstacle in the preparation of coherent complete lab reports.
In R Markdown, a user can combine text with “chunks” of R code, and by “knitting” the R
Markdown document, produce a fully-editable Word document (or HTML or pdf object) for
submission. The rendered document will contain the student’s code, output, and written work.
Presumably, the student would be advised to develop and test the code in R prior to transferring
chunks to the R Markdown document.
Below is a screen shot of an R Markdown document, followed by the Word document created by
it.
80
Markdown sample for GAISE Technology Appendix
A Student
Month xx, 20xx
NOTE: The text below this is automatically generated when the user creates a new R
Markdown document. The user can add text simply. This example uses the Old Faithful
dataset that ships with R.
This is an R Markdown document. Markdown is a simple formatting syntax for authoring
HTML, PDF, and MS Word documents. For more details on using R Markdown see
http://rmarkdown.rstudio.com.
When you click the Knit button a document will be generated that includes both content as
well as the output of any embedded R code chunks within the document. You can embed an R
code chunk like this:
str(faithful)
## 'data.frame': 272 obs. of 2 variables:
## $ eruptions: num 3.6 1.8 3.33 2.28 4.53 ...
81
## $ waiting : num 79 54 74 62 85 55 88 85 51 85 ...
summary(faithful)
##
##
##
##
##
##
##
eruptions
waiting
Min. :1.600 Min. :43.0
1st Qu.:2.163 1st Qu.:58.0
Median :4.000 Median :76.0
Mean :3.488 Mean :70.9
3rd Qu.:4.454 3rd Qu.:82.0
Max. :5.100 Max. :96.0
You can also embed plots, for example:
Note that the echo = FALSE parameter was added to the code chunk to prevent printing of the
R code that generated the plot.
82
A.Student notices that the histogram of duration is bimodal, and that there is a positive
association between eruption waiting time and the duration of eruptions. Also there are two
clusters of points in the scatterplot.
Inspiration:
Baumer, B., Cetinkaya-Rundel, M, Bray, A., Loi, L., and Horton, N. J. (2014), “R
Markdown: Integrating a Reproducible Analysis Tool into Introductory Statistics,”
Technology Innovations in Statistics Education, 8. Available at
http://escholarship.org/uc/item/90b2f5xh.
Editorial (2014), “Journals Unite for Reproducibility,” Nature, 515 (7). 06 November.
Available at http://www.nature.com/news/journals-unite-for-reproducibility-1.16259.
Accessing Real Raw Data online
The third GAISE recommendation is to “Integrate real data with a context and a purpose.”
Appendix C suggests several ways to generate or acquire real data. This section augments those
methods by highlighting web-based avenues to obtain discipline-specific observational,
experimental, and survey data. Instructors seeking real data are advised to begin with visits to
curated data repositories such as:
•
•
•
•
Data and Story Library (DASL), http://dasl.datadesk.com/
Nationmaster – http://www.nationmaster.com/ portal to international economic,
demographic and social data.
Awesome Public Data Sets - https://github.com/caesar0301/awesome-public-datasets by
Xiaming Chen and other contributors
WISE (Web Interface for Statistics Education) has a collection of demonstrations and
tutorials. In addition, a list of data sources posted on their website under helpful links
http://wise.cgu.edu/helpful-links/data-sources/
Accessing Observational Data
Massive volumes of real-time, automatically generated and/or captured data are now available
publicly and for free across disciplines, making it possible to find and use raw data attuned to the
needs of courses and the interests of students. This short section briefly describes how one might
locate and extract such data, using two examples that illustrate both ends of the “ease of use”
spectrum. Because on-line observational data can allow instructors flexibility in choosing and
creating assignments, the classroom illustrations shown in this section are framed as templates
that instructors should tailor to their students and courses.
USER-FRIENDLY ACCESS ILLUSTRATION:
83
Many federal agencies in the U.S. provide user interfaces to build custom queries for
transactional databases. The example here comes from the Bureau of Transportation Statistics
and the On-Time Performance database. According to the BTS website, the database “contains
on-time arrival data for non-stop domestic flights by major air carriers, and provides such
additional items as departure and arrival delays, origin and destination airports, flight numbers,
scheduled and actual departure and arrival times, cancelled or diverted flights, taxi-out and taxiin times, air time, and non-stop distance.” Users can download 109 light-level variables for a
selected month and year, and can filter geographically. Hence, an instructor can obtain data for
nearby airports and recent time periods, selecting variables of particular interest.
The query screen presents a set of drop-down filter selectors and variable checkboxes to specify
which variable fields a user wants to download. After making the selections, the site generates
and delivers a zipped comma-separated-values (csv) file of raw data.
In late 2015, the search screen looked like this:
Prototype Assignment—Student Prompt
Have you ever been on a flight that left the gate on time, only to be frustrated by a long wait
before takeoff? How often do such delays occur? The U.S. Department of Transportation
84
maintains a database with information about the departures and arrivals of every domestic
commercial flight in the United States.
We have a dataset that can help us answer the question, and to compare our local airport with
some of the busiest airports in the country. In the airline industry, the time elapsed between
departing the gate and “wheels up” is known as “Taxi out” time. For this exercise, I have
downloaded from the Bureau of Transportation Statistics and placed it in a file called
{filename}. The file contains several variables about individual flights departing from our
nearest airport (airport code XXX), as well as flights from three airports with very heavy traffic:
Atlanta (ATL), Los Angeles (LAX), and Chicago (ORD) during {MONTH, YEAR}.
For this assignment, the three variables of interest are:
•
•
•
•
•
DayofWeek numeric code for day (1 = Sunday, 2 = Monday, etc.)
Origin
three-letter airport ID code
Carrier
airline identification code
DepTimeBlk standard departure time intervals from the Computerized Reservations
System (CRS)
TaxiOut
taxi out time, in minutes
For the month of {MONTH}, use appropriate graphical and descriptive summaries to investigate
these questions and prompts:
1. On a typical flight that month at our airport, how long did it take for flights to take off
after leaving the gate?
2. How did our taxi out times compare to ATL, LAX and ORD?
3. At our airport, how did the different airlines compare in terms of taxi out times?
4. How (if at all) did taxi out times vary by the day of the week at our airport? Is the
variability similar at the other large airports in the dataset?
5. How (if at all) did taxi out times vary by time of day at our airport?
6. Suppose you are planning to fly out of our airport next month. Would you be inclined to
take this analysis into account in preparing for your flight? Why or why not?
COMPUTING-INTENSIVE DATA ACCESS ILLUSTRATION:
Professional sports have been among the early adopters of the managerial and strategic use of
statistical analysis due in some measure to the technologies that automatically capture data at a
very granular level. Major League Baseball (MLB) has led the way in this regard. With the types
of data available to date, one can investigate questions related to teams, players, plays, and even
individual pitches.
For example, since 2007, MLB has been tracking and publishing measurements of every pitch
thrown in every game of the season (see Inspiration and References below). The technology
behind the data collection is called PITCHf/x, and the relevant MLB website contains XML files
within a hierarchical directory tree structure organized by date. More specifically, to access
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PITCHf/x data for a single game, one first identifies the year, month, date and “game id” for the
game of interest.
The data are freely available in the sense that there is no payment required, but in contrast to the
prior example, actually accessing and preparing the data for analysis is best done by writing code
to automatically scrape dates, games and innings of interest. There are some third-party sites that
help with access, but the MLB site exemplifies the challenges and rewards of the “big data” era:
the available data open the doors to previously unimaginable analysis, but the doors are
complicated to navigate.
This illustration is inspired by a 2010 article in the Journal of Statistics Education by Jim Albert,
a leader in using sports data for instruction. We are aware that sports data examples excite some
students and can alienate others. The point here is to illustrate the availability and challenges of
accessing some web sources, not to advocate the use of this particular type of baseball data.
In Albert’s article, we have a dataset with the following variables:
Prototype Assignment—Student Prompt
In Major League Baseball, successful pitchers combine athletic skill and tactical judgment to
outwit opposing batters. Pitchers vary in many respects, including the variety of pitches they use
(fastballs, curveballs, etc.), the way they sequence pitches, as well as the speed and movement of
their different pitches.
Since the 2007 season, the MLB has used a digital recording system to measure particular
parameters of every pitch thrown in every game. The technology involved is known as
“PITCHf/x” and for this assignment we have a data file called {FILENAME}. This file contains
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all of the games played by our local team, the {TEAM} during the {YEAR} season. In this
assignment, we’ll focus on the pitching performance of our ace pitcher {PITCHER}. Your tasks:
1. Because teams have several pitchers who rotate from game to game, our first task is to
isolate only the data rows involving {PITCHER}. Use software to create a subset of
{FILENAME} that contains only pitches thrown by PITCHER.
2. What types of pitches does {PITCHER} tend to throw, and how often does he throw
each?
3. What were the outcomes of his pitches as the end of the plate appearance?
4. How do the outcomes vary by type of pitch?
5. Are particular pitches more successful at inducing batters to swing and miss?
Of the different pitch varieties, some are distinguished by their “movement,” or the extent to
which they deviate from an imaginary straight line between the pitcher’s hand and home plate. In
the PITCHf/x data, pfx_x and pfx_z represent the movement in the horizontal and vertical
directions respectively. The horizontal break is calculated from a perspective behind the point of
home plate, so that negative values of pfx_x move towards a right-handed batter and away from
a left-handed batter.
Pitches also vary in speed, and PITCHf/x records two speeds: when the ball leaves the pitcher’s
hand and when it crosses the plate.
6. Use software to create a scatterplot of the horizontal and vertical movement of
{PITCHER’s} 4-seam fastballs, curveballs, and change-ups. In the plot, use different
symbols for the three pitch types and vary the intensity of the color by the end_speed of
the pitch (speed arriving at the batter).
7. In plain English, explain what you see in this scatterplot.
Inspiration and References
Albert, J. (2010), “Baseball Data at Season, Play-by-play, and Pitch-by-pitch levels,”
Journal of Statistics Education, 18. www.amstat.org/publications/jse/v18n3/albert.pdf.
Major League Baseball (2010), Pitch F/X data files. Available at
http://gd2.mlb.com/components/game/mlb.
Silver, N. (2015), “The Best and Worst Airlines, Airports and Flights, Summer 2015
Update.” Downloaded June 17, 2015 from http://fivethirtyeight.com/features/the-bestand-worst-airlines-airports-and-flights-summer-2015-update/.
U.S. Department of Transportation, Bureaus of Transportation Statistics (2015),
Database Profile. Available at
http://www.transtats.bts.gov/TableInfo.asp?Table_ID=236.
U.S. Department of Transportation Office of the Assistant Secretary for Research and
Technology (2015), Airline On-Time Performance Data database. Available at
http://www.transtats.bts.gov/Tables.asp?DB_ID=120&DB_Name=Airline%20OnTime%20Performance%20Data&DB_Short_Name=On-Time.
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Accessing Experimental Data
Traditionally, raw experimental data has been proprietary and therefore difficult to obtain. More
recently, we are seeing contemporaneous phenomena including the Open Science, Science
Commons, and Citizen Science movements which all make use of the Internet to advance the
sharing of data. As Dawson (2012) has stated,
“Taking inspiration from the open source software and open access movements, some
scientists are now sharing their lab notebooks and raw experimental data openly online.
Open science is a broad concept that includes these closely related areas of open
notebook science and open data. Advocates of open science believe that there should be
no insider information, and all protocols and results -- even those of failed experiments -should be made visible and open to reuse as soon as possible in open lab notebooks and
data repositories.”
Recently, in the United States, the National Science Foundation has, as a matter of policy,
committed itself to pressing NSF-funded researchers to publish not only results and reports of
research, but to publish raw data as well (NSF 2013).
These developments offer great promise for statistics education to use web browsers and
statistical software to obtain and access experimental data, including the ability to access both
significant and non-significant results drawn for a wide variety of client disciplines.
The following example uses a subset of data contributed to the University of California Irvine
Machine Learning Repository, and it illustrates a common practice of A-B testing in web-based
environments. The data were provided by YouTube, as described in the Student Handout that
follows. This example deals with a substantive domain that should be familiar to most
undergraduates.
Student Handout
YouTube Comedy Slam was a video discovery experiment running on YouTube's version of
labs (called TestTube) for a few months in 2011 and 2012. In this experiment, a pair of videos
was shown to each user, and users were asked to vote for the video they found to be funnier.
Left/right positions of the videos were randomly selected before being presented to users to
eliminate position bias. Videos were selected from a large pool of weekly updated sets of
videos. Users were self-selected visitors to YouTube.
We have provided you a dataset (n = 3,545 observations), drawn from the original sample of
more than 1.1 million preference votes. Each line in this dataset corresponds to one vote over a
pair of YouTube videos. One of the videos was a compilation of amusing footage of cats in
various settings, and the other was a practical joke played on a co-worker by a friend.
Each video is represented by its YouTube video ID (see references for the URLs of each
video). There are three columns in the dataset: Left, Right, and Choice. The first two columns
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just indicate which video ID was shown in which position, and the third column represents the
user’s choice.
Shetty (2012) provides a more complete description of the experimental setting:
Quantifying comedy on YouTube: why the number of o’s in your LOL matter
Posted by Sanketh Shetty, YouTube Slam Team, Google Research
In a previous post, we talked about quantification of musical talent using machine
learning on acoustic features for YouTube Music Slam. We wondered if we could do
the same for funny videos, i.e. answer questions such as: is a video funny, how funny
do viewers think it is, and why is it funny? We noticed a few audiovisual patterns
across comedy videos on YouTube, such as shaky camera motion or audible laughter,
which we can automatically detect. While content-based features worked well for
music, identifying humor based on just such features is AI-Complete. Humor
preference is subjective, perhaps even more so than musical taste.
Fortunately, at YouTube, we have more to work with. We focused on videos uploaded
in the comedy category. We captured the uploader’s belief in the funniness of their
video via features based on title, description and tags. Viewers’ reactions, in the form
of comments, further validate a video’s comedic value. To this end we computed more
text features based on words associated with amusement in comments. These included
(a) sounds associated with laughter such as hahaha, with culture-dependent variants
such as hehehe, jajaja, kekeke, (b) web acronyms such as lol, lmao, rofl, (c) funny and
synonyms of funny, and (d) emoticons such as :), ;-), xP. We then trained classifiers to
identify funny videos and then tell us why they are funny by categorizing them into
genres such as “funny pets”, “spoofs or parodies”, “standup”, “pranks”, and “funny
commercials”.
Next we needed an algorithm to rank these funny videos by comedic potential, e.g. is
“Charlie bit my finger” funnier than “David after dentist”? Raw viewcount on its own
is insufficient as a ranking metric since it is biased by video age and exposure. We
noticed that viewers emphasize their reaction to funny videos in several ways: e.g.
capitalization (LOL), elongation (loooooool), repetition (lolololol), exclamation
(lolllll!!!!!), and combinations thereof. If a user uses an “loooooool” vs an “loool”,
does it mean they were more amused? We designed features to quantify the degree of
emphasis on words associated with amusement in viewer comments. We then trained a
passive-aggressive ranking algorithm using human-annotated pairwise ground truth and
a combination of text and audiovisual features. Similar to Music Slam, we used this
ranker to populate candidates for human voting for our Comedy Slam.
So far, more than 75,000 people have cast more than 700,000 votes, making comedy
our most popular slam category. Give it a try!
Further reading:
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“Opinion Mining and Sentiment Analysis,” by Bo Pang and Lillian Lee.
“A Great Catchy Name: Semi-Supervised Recognition of Sarcastic Sentences in Online
Product Reviews,” by Oren Tsur, Dmitry Davidov, and Ari Rappoport.
“That’s What She Said: Double Entendre Identification,” by Chloe Kiddon and
1. After reading the background material and exploring the data set, briefly describe this
experimental design. To what extent will it be reasonable to generalize from any
conclusions drawn? Explain your thinking.
2. What is the response (dependent) variable in this experiment?
3. What is/are the explanatory (independent) variable(s) in this experiment?
4. Discuss how you intend to use your statistical software to prepare the data for analysis
and then analyze the data from this experiment.
5. Run an appropriate analysis of the data and report on your conclusions.
Teaching Notes:
•
•
Technology is present in three forms in this exercise. First, the experiment is inherently
technologically-based and exemplifies a widely-adopted practice in the design of web
interfaces. Second, the data were obtained on-line and required some manipulation to
create a student-friendly dataset. Finally, students should be expected to perform the
analysis. Depending on the statistical software available to them, instructors may wish to
reformat the data.
The questions listed above should be tailored depending upon course emphasis.
Suggestions to Instructors for further investigation
This example is based on a dataset available at the Machine Learning Repository at the
University of California at Irvine (see references below). Instructors who want to find other
experimental datasets to create an original assignment might consult other sites.
•
•
There are compendia of web resources like http://www.statsci.org/datasets.html or
CAUSEWeb, which both curate datasets as well as links to other data compilations.
Those who teach students in health-related disciplines should visit US government sites
such as http://clinicaltrials.gov/ for a clearer sense of current trends in making shared data
available.
Inspiration and References
Dawson, D. (2012), “Open Science and Crowd Science: Selected Sites and Resources,”
Issues in Science and Technology Librarianship, Spring. Available at
http://www.istl.org/12-spring/internet2.html#online-tools.
“Hilarious Cats” (n.d.) Available at https://www.youtube.com/watch?v=7zCIRPQ8qWc.
National Science Foundation (2013), “National Science Foundation Collaborates with
Federal Partners to Plan for Comprehensive Public Access to Research Results,” Press
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Release 13-030, February 22, 2013. Available at
http://www.nsf.gov/news/news_summ.jsp?cntn_id=127043.
“O susto do gordinho” (n.d.) Available at
https://www.youtube.com/watch?v=W9y6nwBwwyQ.
Shetty, S. (2012), “Quantifying Comedy on YouTube: Why the Number of o’s in your
LOL matter,” Google Research Blog, February 9. Available at
http://googleresearch.blogspot.com/2012/02/quantifying-comedy-on-youtube-why.html.
UC Irvine Machine Learning Repository (2012). Available at
https://archive.ics.uci.edu/ml/datasets/YouTube+Comedy+Slam+Preference+Data#.
Accessing Real Survey Data
In their quest to use real data from client disciplines, instructors have ready access to an
enormous variety of large-scale survey data collected by reputable agencies. Typically, such
datasets are accessible via user-friendly web interfaces that include codebooks and background
information, and many such sites permit selection by variable. This example uses the General
Social Survey (GSS), an annual full-probability, personal interview survey designed to monitor
changes in both social characteristics and attitudes in the United States (NORC 2014b). The GSS
is a project of the National Opinion Research Center (NORC) at the University of Chicago, and
has been administered since 1972.
The NORC website (2014a) provides this brief overview of the survey: “The GSS contains a
standard 'core' of demographic, behavioral, and attitudinal questions, plus topics of special
interest. Many of the core questions have remained unchanged since 1972 to facilitate time-trend
studies as well as replication of earlier findings. The GSS takes the pulse of America, and is a
unique and valuable resource. It has tracked the opinions of Americans over the last four
decades.” Subject areas cover a wide range of social and cultural issues, including attitudes about
government, religion, the workplace, equality, and popular culture. Annually, the sample size is
approximately 2,000 respondents, aged 18 years and above.
Most variables are categorical, using Likert-type scales. Downloads typically include respondent
identifiers, basic demographics (e.g., age, region, gender), as well as interview dates and
sampling weights. The GSS covers a wide variety of topics, so it is suitable for many
introductory courses, but should be of particular value for any instructor teaching an introductory
statistics course with a social science focus.
Due to the changing design and content of websites, this discussion minimizes references to
specific URLs or menus, but a web search for NORC or the General Social Survey should
suffice. At the time of this writing, one should navigate to the main NORC site:
http://www3.norc.org/GSS+Website/
•
From the NORC site, users choose between SPSS or STATA formats. These are
available freely to any user.
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•
Alternatively, the NORC download site also provides links to the GSS Data Explorer, to
the Roper Center at the University of Connecticut and to ICPSR (Inter-university
Consortium for Political and Social Research at the University of Michigan), including
ASCII, SAS, delimited, and R. At the latter two sites, membership and/or fees may be
required.
Users can download multi-year cumulative files or annual complete datasets. Alternatively, one
is able to browse variables by subject, by variable name, or in other ways. Hence, instructors
seeking a dataset suitable for a particular course have considerable flexibility of access.
Questions at the core of the GSS appear annually in the instrument, while others may be included
just once or periodically. For example, a nearly-annual question (NORC 2014c) asks “I am going
to name some institutions in this country. As far as the people running these institutions are
concerned, would you say you have a great deal of confidence, only some confidence, or hardly
any confidence at all in them?... Executive branch of the federal government.” The NORC site
provides detailed documentation for each variable, as well as summary statistics for the
cumulative period 1972–2006. The figure below is a screen capture at the time of this writing
(Fall 2014) of the Subject Index page for this particular question, showing the question text and a
descriptive summary of responses aggregated over the cumulative time period.
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Given the wide-ranging scope of the GSS, instructors can make use of the data for a variety of
descriptive and inferential assignments and examples, and highlight important concepts in survey
construction and/or interpretation of raw data. Here are some possible activities related to this
particular question. Note that the frequency table provided above reports both the raw number of
responses (N) and the weighted number of responses (NW). The reported percentages use the
weighted counts divided by the number of valid cases (33,652). The difference between
weighted and unweighted counts is probably beyond the scope of most introductory courses, but
instructors should preface these questions by noting that survey researchers typically use
weighting as a way to compensate for the fact that some demographic groups are over- or underrepresented by a particular sampling method.
1. Trained employees of NORC administer the General Social Survey. The
“PreQuestion Text” and “Literal Question” and the instruction “READ EACH ITEM;
CODE ONE FOR EACH” are worded quite precisely. Why do you think the General
Social Survey administrators are so particular about the wording of questions? What
difference would it make if an interviewer asked the question using different
wording?
2. Before analyzing the responses to this question, look closely at the Categories listed.
The first three are straightforward enough to interpret, but “NAP,” “DK,” and “NA”
are ambiguous. Visit the NORC website and search for these three abbreviations.
Report briefly on what you find.
3. Below the heading “Summary Statistics,” notice the phrase “This variable is
numeric.” Is it? What do you think the General Social Survey folks mean by this?
4.
In the United States, the Federal government consists of three branches: executive,
legislative, and judicial. In the aggregate from 1972 through 2006, approximately
17.2% of respondents expressed “a great deal” of confidence in the executive branch.
How does that compare to confidence in the other two branches? Visit the NORC site
(or use data provided by your instructor) to locate the corresponding variables for the
legislative and judicial branches. Write a few short sentences comparing respondents’
confidence in the three branches.
5. Looking at these aggregated responses over a period of more than 30 years may raise
some questions in your mind. Write down one or two questions about confidence in
the institutions of government that you would like to investigate further using GSS
data.
Inspiration:
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National Opinion Research Center (2014a), General Social Survey. Available at
http://www3.norc.org/GSS+Website/.
National Opinion Research Center (2014b), National Data Program for Social Sciences.
Available at
http://www3.norc.org/GSS+Website/About+GSS/National+Data+Program+for+Social+S
ciences/.
National Opinion Research Center (2014c), Browse GSS Variables Subject Index.
Available at
http://www3.norc.org/GSS+Website/Browse+GSS+Variables/Subject+Index/.
Using Games and Other Virtual Environments
Computer gaming has become a large source of entertainment for many people, including
college students. In the past few years, energy has been spent to design online games for use in
statistics classrooms. The hope is that by using computer games in the statistics classroom, a
higher level of engagement can occur. There are multiple ways that we can use games in the
classroom.
Real Data: Students can have personal experiences with games. Students can put together jigsaw
puzzles, complete crossword puzzles or play some other quick online game. The students can
then analyze the completion times or other variables from these games.39
Gathering Virtual Data: Sometimes data from virtual reality environments can also be used to
engage students. For example, students can experience trying to collect data from an endangered
species40 or conduct a health survey across an entire Island or group of Islands. 41
Experimental Design: Another way to incorporate the use of games into the classroom is by having
students think about what factors affect the time to win a game or the points earned in a game.
For example, does gender, the amount of hints, color of the pieces, and/or seeing a preview of a
game affect the chance of winning the game?
Statistical Concept: With some games, players can only advance or move ahead in the game if they
have mastered a statistical concept. By learning and applying a statistical concept, you are able
to win. For example, perhaps by analyzing a set of past attempts, a more successful method of
getting to the goal can be discovered. Or, perhaps studying the conditional probabilities of moves
or studying a scatterplot may increase the number of points a player has in the game.42
Inspiration:
39
Games and written lab activities can be found at this website http://web.grinnell.edu/individuals/kuipers/stat2labs/.
Other statistical games and puzzles can be found online through a google search.
40
For example, Shonda Kuiper has designed TigerStat that can be used to gather information about tigers:
http://statgames.tietronix.com/TigerSTAT/.
41
Michael Bulmer has also designed the Islands for data collection across a virtual population:
http://islands.smp.uq.edu.au/login.php
42
Some of these games can be found at http://play.ccssgames.com/
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Erikson, T. (2013), “Designing Games for Understanding in a Data Analysis
Environment,” Technology Innovations in Statistics Education, 7. Available at
http://escholarship.org/uc/item/31t469kg.
Erikson, T., and Triggs, M. (2014), “An Early Look at Rich Learning Analytics: Statistics
Students Playing ‘Markov’,” ICOTS 9 Proceedings. Available at
http://icots.info/9/proceedings/pdfs/ICOTS9_9G1_ERICKSON.pdf .
Kuiper, S., and Sturdivant, R. (2014), “Using Fun and Games to Engage Real-world
Learning,” eCOTS 14 Workshop. Available at
https://www.causeweb.org/ecots/ecots14/34/.
Sturdivant, R., Jackson, J., and Cummiskey, K. (2013), “TigerStat: An Immersive 3-D
Game for Statistics Classes,” CAUSE webinar. Available at
https://www.causeweb.org/webinar/activity/2013-04/.
Bulmer, M., and Haladyn, J.K. (2011), “Life on an Island: A Simulated Population to
Support Student Projects in Statistics,” Technology Innovations in Statistics Education, 5.
Available at http://escholarship.org/uc/item/2q0740hv.
Baglin, J., Bedford, A., and Bulmer, M. (2013), “Students’ Experiences and Perceptions
of using a Virtual Environment for Project-based Assessment in an Online Introductory
Statistics Course,” Technology Innovations in Statistics Education, 7. Available at
http://escholarship.org/uc/item/137120mt.
Student Handout
Your instructor will present you with a game.43 Take a few minutes to familiarize yourself
with the game.
Part One: As you familiarize yourself with the game, what are you interested in discovering?
List a few of these questions here:
1.)
2.)
3.)
Part Two: Pick one of your above questions and think about how you would gather evidence to
answer it. Here are some issues that you should consider.
1. What type of data would you need to collect?
43
There are many online games where data can be collected. You can even use a traditional puzzle or board puzzle.
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2. Would these variables be categorical or quantitative?
3. What type of lurking variables would you need to be concerned about? Why?
4. How would you include random sampling and/or random allocation?
5. What statistical method have we discussed in class could be used to analyze that data?
Part Three: Write up a study protocol. Be very detailed. Write the instructions for how an
experimenter would go about conducting this experiment.
Teaching Note:
After this activity has been completed, one possible next step is to have the class pick one
of the study ideas. The class can then collect data and analyze it. It might be a good idea
for the students to complete the game outside of class time. Some students may take
longer to complete certain puzzles and you don’t want to accidently embarrass someone
who takes twice as long as other students. If you decide to have students complete the
puzzle outside of class, you can then also discuss what lurking variables this might
introduce. If you decide to complete the puzzle in class, another option would be to give
the students one minute to complete as much of the puzzle as they can and then measure
percentage of completion.
Real Time Response
While not limited to statistics classrooms, real time responses systems (clickers) can be an asset
in achieving the GAISE recommendations. The GAISE recommendations encourage instructors
to use technology for computation and emphasizing concepts. Real time responses allow us to
explore concepts, as well as gather data to analyze in the classroom.
Initially, real time response systems,44 or audience response systems, started as devices similar to
TV remotes. The device, commonly known as a clicker, could only be used to respond in class to
a teacher’s multiple choice question posted on a projection screen. Over the past decade or more,
these devices have evolved. Devices that only allow for multiple choice entry are still available,
and some also allow for numeric entry. Moreover, now there are systems that allow the students
to enter information from their computers, tablets or even phones. Questions sometimes even
44
Some of these devices include: specific devices: “clickers” such as iClicker or H~ITT; web based services such as Learning Catalytics, TopHat,
b.socrative.com, Google Forms, Survey Monkey, Qualtrics, Poll Anywhere, Course Management Software
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appear directly on the devices, and students are no longer limited to just multiple choice
questions. Students can enter numerical values, equations, and even draw on the screen. These
responses can then be combined and shared with the class. There is a vast array of options in
how anonymous the responses from the students can be. The student’s responses could be made
anonymous from both other students and even from the instructor (in some cases). Having
various options for anonymity allows for flexibility in teaching methods.
For example, some systems post a summary of responses provided by the class – the percentage
who answered A, B, C, etc. This allows students to be able to judge where they stand in the class.
Since this data is summarized, it provides a layer of protection for a shy student who might not
ordinarily participate.
Real time response systems allow us to receive responses synchronously in a face-to-face class
from all students. However, these systems can also be used for completion of assignments
outside of class. The questions can be assigned for homework and recorded on a real time
response system outside of class.
Some of the new systems even help enable team-based answering. For example, the system first
asks a question or several questions which are answered by the individual student. Then, the
students form teams. The team could be created by the instructor, self-selected by the students, or
created by the real time response system based on individual student answers. Then, the team
discusses the questions, and answers them again as a team. Some systems even show what each
member of the team initially answered, enabling better team discussion.
The real time class responses can be used in multiple ways in the face-to-face classroom
environment. Some of these examples include:
•
•
•
•
•
•
Review the previous day’s assignment or ask questions about an assigned reading
Expose misconceptions and use them as talking points
Illustrate a concept
Collect data to analyze
Allow instructors to determine if they are going too fast/ too slow
Supplement applets by helping to focus the students’ explorations of the applet. For
example, first ask the students to answer a series of questions, then have them play with
an applet and re-answer the same series of questions.
Future Direction of Real Time Response
With the presence of cloud-based computing, more opportunities will become available for
students to collaborate in real time but separate spaces. For example, students might work
together to create one document45 or annotate an existing document46.
45
For example, using Goggle Docs or etherpad.
For example, using ClassroomSalon (www.classroomSalon.com) or https://oeit.mit.edu/gallery/projects/nb-pdfannotation-tool
46
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Best Practices and Ideas from Statistics Education Literature
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Use a small number of clicker questions with a clear defined reason for each question and its
placement in the lesson.
o From:
McGowan, H., and Gunderson, B. (2010), “A Randomized Experiment Exploring
How Certain Features of Clicker Use Effect Undergraduate Student’s Engagement
and Learning in Statistics,” Technology Innovations in Statistics Education, 4.
Available at http://escholarship.org/uc/item/2503w2np .
•
Use clickers to promote understanding of concepts, not just calculation, for topics such as
inference and applets.
o See the following for a compilation of ideas:
Kaplan, J. (2011), “Innovative Activities: How Clickers can Facilitate the use of
Simulations in Large Lecture Classes,” Technology Innovations in Statistics
Education, 5. Available at http://escholarship.org/uc/item/1jg0274b/.
•
Ask concept questions or questions that investigate common misconceptions.
o See the following for more information:
Perez, C, and Lane, D. (2012), "Simulations, Audience Response Systems and the
Classroom: Engaging the Modern Student,” eCOTS 12 breakout session. Available at
https://www.causeweb.org/ecots/ecots12/breakouts/8/
Best Practices and Ideas from Education Literature from Other Disciplines
•
•
For a summary of best practices from various academic disciplines, including life sciences
and physics see the following:
Caldwell, J. (2007), “Clickers in Large Classrooms: Current Research and Best Practice
Tips,” CBE Life Sciences Education, Spring, 6. Available at
http://ncbi.nlm.nih.gov/pmc/articles/PMC1810212/.
For a summary of experiences with Peer Instruction:
Lasry, N., Mazur, E., and Watkins, J. (2008), “Peer Instruction: From Harvard to
Community Colleges,” American Journal of Physics, 76, 1066-1069. Available at
http://dx.doi.org/10.1119/1.2978182 .
EXAMPLE ASSIGNMENT 1: USING REAL TIME RESPONSE AS AN EXAMPLE OF HOW TO BRING ATTENTION TO A
MISCONCEPTION.
Teacher Resources: Slides Posing Questions
Which of the following graphs has the smallest standard deviation?
98
A
5
Frequency
4
3
2
1
0
1
2
3
a
4
5
B
9
8
Frequency
7
6
5
4
3
2
1
0
1
2
3
b
4
5
4
5
C
14
12
Frequency
10
8
6
4
2
0
1
2
3
c
1. First have the students respond on their own using their own device.
2. After the students have responded, have the students re-answer the question after a
team discussion.
Inspiration:
99
•
•
Kaplan, J., Gabrosek, J., Curtiss, P., and Malone, C. (2014), “Investigating Student
Understanding of a Histogram,” Journal of Statistical Education, 22. Available at
http://www.amstat.org/publications/jse/v22n2/kaplan.pdf.
Cooper, L.L., and Shore, F.S. (2010), “The Effects of Data and Graph Type on Concepts
and Visualizations of Variability,” Journal of Statistical Education, 18. Available at
http://www.amstat.org/publications/jse/v16n2/cooper.html.
Teaching Notes:
A known misconception is that students seem to assume that flatter histograms mean less
variation.
• The correct answer is C. In histogram C, the average distance of points from the mean is
less than in the other histograms. In histograms A and B, more of the points are a further
distance from the mean.
EXAMPLE ASSIGNMENT 2: USING A REAL TIME RESPONSE AS A WAY TO GUIDE A STUDENT’S EXPERIENCE WITH AN
APPLET.
•
Teacher Resources: Slides Posing Questions
1. Do outliers affect the value of the standard deviation?
a.) No
b.) Yes
2. Suppose that your data set has a point that is much lower than the rest. What type of
effect (if any) would this have on the value of the standard deviation?
a.) It would make it larger.
b.) It would make is smaller.
c.) It would stay the same.
d.) Unable to be determined.
3. Suppose that your data set has a point that is much higher than the rest. What type of
effect (if any) would this have on the value of the standard deviation?
a.) It would make it larger.
b.) It would make is smaller.
c.) It would stay the same.
d.) Unable to be determined.
Inspiration:
Perez, C., and Lane, D. (2012), "Simulations, Audience Response Systems and the
Classroom: Engaging the Modern Student,” eCOTS 12 breakout session. Available at
https://www.causeweb.org/ecots/ecots12/breakouts/8/ .
Teaching Notes:
100
•
•
•
•
Correct Answers: 1.b, 2. a 3. a
In order to focus students’ attention on an applet, it is advised that the students be
aware of the questions they are investigating before being exposed to the applet. The
real time response systems help with this by focusing students’ thoughts before their
experience using the applet and then having them re-evaluate their answers at the end
of the experience.
Sometimes, students think that adding a lower point to a data set will cause the
standard deviation to get smaller, similar to what would happen with the mean.
You could also ask the students to explore this concept with their calculators or
statistical software if you do not have internet access to an applet.
EXAMPLE ASSIGNMENT 3: ILLUSTRATING THE SAMPLING DISTRIBUTION OF THE SAMPLE PROPORTION
Teacher Resources: Slides Posing Questions47
When you flipped the coin 1 time, what proportion of heads did you get? _______
When you flipped the coin 5 times, what proportion of heads did you get? ________
When you flipped the coin 25 times, what proportion of heads did you get? ________
Student Handout
Flip a fair coin one time, five times and then twenty-five times. Enter your responses below
and enter the responses in the survey mechanism. After all students have entered their data,
you will be given the data from all students to graph. Make a graph of the results for n = 1, n =
5, and n = 25.
Your Response
Sketch of results
n=1
n=5
47
This set of questions is designed for response systems that allow for quantitative responses; however, with a little
work, an instructor can create multiple responses that would work. After the responses have been received, the
instructor will need to download the results and distribute them to the students. The instructor can also demonstrate
making the histograms.
101
n = 25
Based on your observations above . . .
• What happens to the center as n increases?
•
What happens to the standard deviation as n increases?
•
What happens to the shape as n increases?
•
In your own words, why does increasing the number of flips lead to these results?
Inspiration:
Taylor, L., and Doehler, K. (2014), “Using Online Surveys to Promote and Assess
Learning,” Teaching Statistics, 36, 34- 40.
Teaching Notes:
•
•
The objective of this activity is to explore the concepts of the sampling distribution of the
sample proportion.
Have the students flip a coin and record the proportion of heads for their series of trials.
Once they have completed the flips, they should enter the data into the “Real Time”
response system.
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•
The students should notice that as n increases, the bell shaped distribution starts to
appear, the amount of variation decreases, but the center stays at 0.548.
Kaplan, J. (2011), “Innovative Activities: How Clickers can Facilitate the use of
Simulations in Large Lecture Classes,” Technology Innovations in Statistics Education,
5. Available at http://escholarship.org/uc/item/1jg0274b/.
48
This activity focuses on flipping a fair coin because coins are easily accessible to most students and teachers;
however, you could alter the activity so that the probability of success was something other than 0.5.
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APPENDIX E:
E: Examples of Assessment Items
Well-designed assessment items help to determine whether students understand key statistical
concepts. Since the original GAISE report was written in 2005, there have been many
improvements in the ways that instructors and institutions determine whether students have met
the learning outcomes for introductory statistics courses.
Students value that which is assessed49, so it is important that we assess student learning in a
manner consistent with our stated goals. Good items assess the development of statistical
thinking and conceptual understanding, preferably using technology and real data.
Below, we present exemplary assessment items, some of which include commentary. We also
present a few items that are not strong, with suggestions on how they can be improved. Finally,
we present advice on constructing a rubric when assessing a project report or presentation.
Examples of Exemplary Assessment Items
We begin by providing examples of exemplary assessment items with commentary about the
items. We regard these as exemplary because they reflect the GAISE recommendations of setting
problems in realistic, meaningful contexts; they are data-based; and they go beyond calculation
to probe deeper understanding of concepts.
ITEM 1
Scientists use metal bands to tag penguins. Do the bands harm the birds?
Researchers investigated this question with a sample of 100 penguins near Antarctica. All of
these penguins had already been tagged with RFID chips, and the researchers randomly assigned
50 of them to receive a metal band on their flippers in addition to the RFID chip. The other 50
penguins did not receive a metal band. Researchers then kept track of which penguins survived
for the 4.5-year study and which did not. They found that 16 of the 50 penguins with a metal
band survived, compared to 31 of the 50 penguins without a metal band.
1. Calculate the difference in the proportions who survived between the two groups.
2. The p-value for comparing the two group's survival proportions turns out to be 0.005. Explain
(as if to someone who has not studied statistics) what this p-value means: This is the probability
of…
3. Summarize your conclusion from this p-value. Do bands hurt the penguins? Be sure to address
the issue of causation as well as the issue of significance. Also justify your conclusion.
49
In general, we want students to interpret results more than we want them to produce results. If we ask a True/False question, we want the
student to explain why a statement is true or is false, so that we can assess the thinking that lead to the answer chosen. However, sometimes the
practicalities of teaching a large class mean that an appropriate exam question might be a multiple choice item that does not ask for explanation.
104
ITEM 2
Suppose that 20% of undergraduate students at a university own an iPad and 60% of graduate
students at the university own an iPad. Is it reasonable to conclude that 40% (the average of 20%
and 60%) of all students at the university (undergraduate and graduate students combined) own
an iPad? Explain why or why not, as if to a college student who has not taken a statistics class.
ITEM 3
Suppose that you take a random sample of 100 houses currently for sale in California. Does the
Central Limit Theorem suggest that a histogram of the house prices in the sample will display an
approximately normal distribution? Explain briefly.
ITEM 4
Does everyone who scores below the median on this exam necessarily have a negative z-score
for this exam? Explain.
ITEM 5
Describe a situation where a third variable could be masking the relationship between two
variables.50
ITEM 6
Suppose that Nancy, who is statistically savvy, wants to compare the average costs of textbooks
for students at her college between the fall and spring semesters of last year. Let µ F and µ S
represent the two population means. You may assume that Nancy has taken several statistics
courses and knows a lot about statistics, including how to interpret confidence intervals and
hypothesis tests. You have random samples from each semester and are to analyze the data and
write a report. You seek advice from four persons:
1. Rudd says, “Conduct an alpha=0.05 test of H0: µ F = µ S vs. HA: µ F ≠ µ S and tell Nancy whether
you reject H0.”
2. Linda says, “Report a 95% confidence interval for µ F - µ S.”
3. Steve says, “Conduct a test of H0: µ F = µ S vs. HA: µ F ≠ µ S and report to Nancy the p-value
from the test.”
4. Gloria says, “Compare y1 to y 2 . If y1 > y 2 , then test H0: µ F = µ S vs. HA: µ F > µ S using
alpha =0.05 and tell Nancy whether you reject H0. If y1 < y 2 , then test H0: µ F = µ S vs. HA: µ F <
µ S using alpha = 0.05 and tell Nancy whether you reject H0.”
50
Sample solution: For an observational study which assessed the association between coffee drinking and cancer, smoking status could mask (or
``confound") the relationship, since smoking could be associated with both coffee drinking and cancer (see also Appendix B, Multivariable
Thinking).
105
Rank the four pieces of advice from worst to best and explain why you rank them as you do.
That is, explain what makes one better than another.
Examples of Assessment Items Needing Improvement and
Commentary
We next give some examples of assessment items with problems and commentary about the
nature of the difficulty. We recommend that questions such as these should either be improved as
discussed in the following section or dropped from use.
Assessment items to avoid using on tests: traditional True/False, pure computation without a
context or interpretation, items with too much data to enter and compute or analyze, or items
that only test memorization of definitions or formulas.
ITEM 7
A teacher taught two sections of elementary statistics last semester, each with 25 students, one at
8:00 a.m. and one at 4:00 p.m. The means and standard deviations for the final exams were 78
and 8 for the 8:00 a.m. class and 75 and 10 for the 4:00 p.m. class. In examining these numbers,
it occurred to the teacher that the better students probably sign up for 8:00 a.m. class. So she
decided to test whether the mean final exam scores were equal for her two groups of students.
State the hypotheses and carry out the test.51
ITEM 8
An economist wants to compare the mean salaries for male and female CEOs. He gets a random
sample of 10 of each and does a t-test. The resulting p-value is 0.045.52
1. State the null and alternative hypotheses.
2. Make a statistical conclusion.
3. State your conclusion in words that would be understood by someone with no training in
statistics.
ITEM 9
Which of the following gives the definition of a p-value?53
A. It's the probability of rejecting the null hypothesis when the null hypothesis is true.
B. It's the probability of not rejecting the null hypothesis when the null hypothesis is true.
C. It's the probability of observing data as extreme as that observed.
D. It's the probability that the null hypothesis is true.
Critique: The teacher has all the population data so there is no need to do statistical inference. In addition, the
proposed design has serious flaws in terms of statistical practice.
52
Critique: The question doesn't address the conditions necessary for a t-test, and with the small sample sizes, they
are almost surely violated here. Salaries are almost surely skewed.
53
Critique: None of these answers is quite correct. Answers B and D are clearly wrong; answer A is the level of
significance; and answer C would be correct if it continued “…or more extreme, given that the null hypothesis is
true.”
51
106
Examples Showing Ways to Improve Assessment Items
ITEM 9 (REVISITED)
Which of the following gives the definition of a p-value?
CHANGED TO:
A randomized trial of the use of bed nets to prevent malaria in sub-Saharan Africa yielded a pvalue of 0.001. Without resorting to jargon, interpret this result in the context of this study to
someone without background knowledge of statistics.54
True/False items, even when well-written, do not provide much information about student
knowledge because there is always a 50% chance of getting the item right without any
knowledge of the topic. One approach is to change the items into forced-choice questions with
three or more options.
ITEM 10
The value of the standard deviation of a data set depends on the center of the distribution. True
or False
CHANGED TO:
Does the size of the standard deviation of a data set depend on the center of the distribution?
A. Yes, the higher the mean, the higher the standard deviation.
B. Yes, because you have to know the mean to calculate the standard deviation.
C. No, the size of the standard deviation is not affected by the location of the distribution.
D. No, because the standard deviation only measures how the values differ from each other, not
how they differ from the mean.
ITEM 11
A correlation of +1 indicates a stronger association than a correlation of -1. True or False
REWRITTEN AS:
A recent article in an educational research journal reports a correlation of +0.8 between math
achievement and overall math aptitude. It also reports a correlation of -0.8 between math
achievement and a math anxiety test. Which of the following interpretations is the most correct?
A. The correlation of +0.8 indicates a stronger relationship than the correlation of -0.8.
B. The correlation of +0.8 is just as strong as the correlation of -0.8.
C. It is impossible to tell which correlation is stronger.
Context is important for helping students see and deal with statistical ideas in real-world
situations.
54
Sample solution: If bed nets were not associated with malaria prevalence then we'd only be likely to see a result this extreme or more extreme
one time out of a thousand. Therefore we conclude that bed nets are very likely to prevent malaria.
107
ITEM 12
Once it is established that X and Y are highly correlated, what type of study needs to be done to
establish that a change in X causes a change in Y?
A CONTEXT IS ADDED:
A researcher is studying the relationship between an experimental medicine and T4 lymphocyte
cell levels in HIV/AIDS patients. The T4 lymphocytes, a part of the immune system, are found at
reduced levels in patients with the HIV infection. Once it is established that the two variables –
dosage of medicine, and T4 cell levels – are highly correlated, what type of study needs to be
done to establish that a change in dosage causes a change in T4 cell levels?
A. correlational study
B. controlled experiment
C. prediction study
D. survey
Try to avoid repetitious/tedious calculations on exams that may become the focus of the
problem for the students at the expense of concepts and interpretations.
ITEM 13
It was claimed that 1 out of 5 cardiologists takes an aspirin a day to prevent hardening of the
arteries. Suppose the claim is true. If 1,500 cardiologists are selected at random, what is the
probability that at least 275 of the 1,500 take an aspirin a day?55
ITEM 14
A first-year program course used a final exam that contained a 20-point essay question asking
students to apply Darwinian principles to analyze the process of expansion in major league sports
franchises. To check for consistency in grading among the four professors in the course, a
random sample of six graded essays were selected from each instructor. The scores are
summarized in the table below. Construct an ANOVA table to test for a difference in means
among the four instructors.
Instructor
Affinger
Beaulieu
Cleary
Dean
18
14
19
17
11
14
20
14
Scores
10
11
15
17
12
14
19
15
15
11
19
18
12
14
16
15
ITEM 14 (REVISITED)56
55
Critique: This problem requires use of software to calculate the exact binomial or use of the normal approximation to the binomial. Computer
output might be provided to augment this question and facilitate solution.
56
Critique: The version of the question above requires a fair amount of pounding on the calculator to get the results and never even asks for an
interpretation. The revision below still requires some calculation (which can be adjusted depending on the amount of computer output provided)
but the calculations can be done relatively efficiently---especially by students who have a good sense of what the computer output is providing.
108
A first-year program course … (same intro as above) … The scores are summarized in the
table below, along with some descriptive statistics for the entire sample and a portion of the oneway ANOVA output.
Descriptive Statistics
Variable
N
Mean Median
Score
24.00
15.00 15.00
TrMean
15.00
StDev SEMean
2.92 0.60
One-way Analysis of Variance
***ANOVA TABLE OMITTED***
Level
Affinger
Beaulieu
Cleary
Dean
N
6
6
6
6
Mean
13.00
13.00
18.00
16.00
StDev
2.97
1.55
2.00
1.55
Pooled StDev = 2.098
1. Unfortunately, we are missing the ANOVA table from the output. Use the information given
above to construct the ANOVA table and conduct a test (5% level) for any significant
differences among the average scores assigned by the four instructors. Be sure to include
hypotheses and a conclusion. If you have trouble getting one part of the table that you need to
complete the rest (or the next question), make a reasonable guess or ask for assistance (for a
small point fee).
2. After completing the ANOVA table, construct a 95% confidence interval for the average score
given by Dr. Affinger. Note: Your answer should be consistent with the graphical display.
109
Additional Examples of Good Assessment Items
ITEM 15
A study found that individuals who lived in houses with more than two bathrooms tended to have
higher blood pressure than individuals who lived in houses with two or fewer bathrooms. Can a
cause-and-effect conclusion be drawn from this? Why or why not?
ITEM 16
Researchers took random samples of subjects from two populations and applied a test to the data;
the p-value for the test, using a non-directional (one-sided) alternative, was 0.06. For each of the
following, say whether the statement is true or false and why.
1. There is a 6% chance that the two population distributions really are the same.
2. If the two population distributions really are the same, then a difference between the two
samples as extreme as the difference that these researchers observed would only happen 6% of
the time.
3. If a new study were done that compared the two populations, there is a 6% probability that H0
would be rejected again.
4. If alpha = 0.05 and a directional alternative were used, and the data departed from H0 in the
direction specified by the alternative hypothesis, then H0 would be rejected.
ITEM 17
As the name suggests, the Old Faithful geyser in Yellowstone National Park has eruptions that
come at fairly predictable intervals, making it particularly attractive to tourists. Here is a boxplot
of the times between eruptions recorded by an observer.
110
You are a busy tourist and have only 10 minutes to sit around and watch the geyser. But you can
choose when to arrive. If the last eruption occurred at noon, what time should you arrive at the
geyser to maximize your chances of seeing an eruption?
1. 12:50pm
2. 1:00pm
3. 1:05pm
4. 1:15pm
5. 1:25pm
Roughly, what is the probability that in the best 10-minute interval, you will actually see the
eruption?
1. 5%
2. 10%
3. 20%
4. 30%
5. 50%
6. 75%
111
A simple measure of how faithful is Old Faithful is the interquartile range. What is the
interquartile range, according to the boxplot above?
1. 10 minutes
2. 15 minutes
3. 25 minutes
4. 35 minutes
5. 50 minutes
6. 75 minutes
Not only are you a busy tourist, you are a smart tourist. Having read about Old Faithful, you
understand that the time between eruptions depends on how long the previous eruption lasted.
Here's a box plot indicating the distribution of inter-eruption times when the previous eruption
duration was less than three minutes.
You can easily ask the ranger what was the duration of the previous eruption. What is the best
10-minute interval to return (after a noon eruption) so that you will be most likely to see the next
eruption, given that the previous eruption was less than three minutes in duration?
1. 12:30 to 12:40
2. 12:40 to 12:50
3. 12:50 to 1:00
112
4. 1:15 to 1:25
5. 1:25 to 1:35
How likely are you to see an eruption if you return for the most likely 10-minute interval?
1. 5%
2. 10%
3. 20%
4. 30%
5. 50%
6. 75%
ITEM 18
An article on the CNN web page begins with the sentence, “Family doctors overwhelmingly
believe that religious faith can help patients heal, according to a survey released Monday.”
Later, the article states, “Medical researchers say the benefits of religion may be as simple as
helping the immune system by reducing stress,” and Dr. Harold Koenig is reported to say that
“people who regularly attend church have half the rate of depression of infrequent churchgoers.”
Use the language of statistics to critique the statement by Dr. Koenig and the claim, suggested by
the article, that religious faith and practice help people fight depression. You will want to select
some of the following words in your critique: observational study, experiment, blind, doubleblind, precision, bias, sample, spurious, confounding, causation, association, random, valid, and
reliable.
ITEM 19
A student weighed a sample of 100 industrial diamonds. She found that the sample average
weight was 4.80 grams and the SD was 0.28 grams. In the context of this setting, explain what is
meant by the sampling distribution of an average.
ITEM 20
A gardener wishes to compare the yields of three types of pea seeds---type A, type B, and type
C. She randomly divides the type A seeds into three groups and plants some in the east part of
her garden, some in the central part of the garden, and some in the west part of the garden. Then,
she does the same with the type B seeds and type C seeds.
1. What kind of experimental design is the gardener using?
2. Why is this kind of design used in this situation? (Explain in the context of the situation.)
ITEM 21
The scatterplot shows how divorce rate and marriage rate (both as number per year per 1000
adults) are related for a collection of 10 countries. The regression line has been added to the
plot.
113
1. The U.S. is not one of the 10 points in the original collection of countries. It happens that the
U.S. has a higher marriage rate than any of the 10 countries. Moreover, the divorce rate for the
U.S. is higher than one would expect, given the pattern of the other countries. How would
adding the U.S. to the data set affect the regression line? Why?
2. Think about the scatterplot and regression line after the U.S. has been added to the data set.
Provide a sketch of the residual plot. Label the axes and identify the U.S. on your plot with a
triangle.
ITEM 22
Researchers wanted to compare two drugs, formoterol and salbutamol, in aerosol solution to a
placebo for the treatment of patients who suffer from exercise-induced asthma. Patients were to
take a drug or the placebo, do some exercise, and then have their “forced expiratory volume”
measured. There were 30 subjects available.
1. Should this be an experiment or an observational study? Why?
2. Within the context of this setting, what is the placebo effect?
3. Briefly explain how to set up a randomized blocks design (RBD) here.
4. How would an RBD be helpful? That is, what is the main advantage of using an RBD in a
setting like this?
ITEM 23
For each of the following three settings, state the type of analysis you would conduct (e.g., onesample t-test, regression, chi-square test of independence, chi-square goodness-of-fit test, etc.) if
you had all the raw data and specify the explanatory and response variable on which you would
perform the analysis, but do not actually carry out the analysis.
1. A student measured the effect of exercise on pulse for each of 13 students. She measured
pulse before and after exercise (doing 30 jumping jacks) and found that the average change was
55.1 and the SD of the changes was 18.4. How would you analyze the data?
114
2. Three HIV treatments were tested for their effectiveness in preventing progression of HIV in
children. Of 276 children given drug A, 259 lived and 17 died. Of 281 children given drug B,
274 lived and seven died. Of 274 children given drug C, 264 lived and 10 died. How would you
analyze the data?
3. A researcher was interested in the relationship between blood pressure and physical activity.
He measured the blood pressure and weekly total number of steps from a Fitbit for 125 women.
How would you analyze these data?
ITEM 24
To compare a quantitative response variable across four groups, I selected random samples from
each of the four groups and constructed parallel dotplots to compare the distributions across the
four groups. I then conducted a test of H0: µ 1 = µ 2 = µ 3 = µ 4 and rejected H0 at the alpha = 0.05
level. I also tested H0: µ 1 = µ 2 = µ 3 and rejected H0 at the alpha = 0.05 level. However, when I
tested H0: µ 2 = µ 3 using alpha = 0.05, I did not reject H0. Likewise, when I tested H0: µ 1 = µ 4
using alpha = 0.05, I did not reject H0.
1. Sketch a graph of the parallel dotplots of the data. That is, based on what I told you about the
tests, you should have an idea of how the data look. Use that idea to draw a graph. Indicate the
sample means with triangles that you add to the dotplots.
2. It is possible to get data with the same sample means that you graphed in part 1, but for which
the hypothesis H0: µ 1 = µ 2 = µ 3 = µ 4 is not rejected at the alpha = 0.05 level. Provide a graph of
this situation. That is, keep the same sample means (triangles) you had from part 1, but show
how the data would have been different if H0 were not to be rejected.
ITEM 25
Students collected data on a random sample of 12 breakfast cereals. They recorded x = fiber (in
grams/ounce) and y = price (in cents/ounce). A scatterplot of the data shows a linear relationship.
The fitted regression model is
ŷ = 17.42 + 0.62x
The sample correlation coefficient (r) is 0.23. The standard error of the sample slope is 0.81.
Also, sy|x = 3.1.
1. Find r2 and interpret r2 in the context of this problem.
2. Suppose a cereal has 2.63 grams of fiber/ounce and costs 17.3 cents/ounce. What is the
residual for this cereal?
3. Interpret the value of sy|x in the context of this problem. That is, what does it mean to say that
sy|x = 3.1?
4. In the context of this problem, explain what is meant by “the regression effect.”
115
ITEM 26
Give a rough estimate of the sample correlation for the data in each of the scatterplots below.
ITEM 27
Identify whether a scatterplot would or would not be an appropriate visual summary of the
relationship between the variables. In each case, explain your reasoning.
1. Blood pressure and age
2. Region of country and opinion about stronger gun control laws
3. Verbal SAT and math SAT score
4. Handspan and gender (male or female)
ITEM 28
The paragraphs that follow each describe a situation that calls for some type of statistical
analysis. For each, you should:
1. Give the name of an appropriate statistical procedure to apply (from the list below). You may
use the same procedure more than once, and some questions might have more than one correct
answer.
2. In some problems, you will also be given a p-value. Use it to reach a conclusion for that
specific situation. Be sure to say something more than just Reject H0 or Fail to Reject H0.
(Assume a 5% significance level.)
Some statistical procedures you might choose:
Confidence interval (for a mean, p, …)
Determining sample size
Test for a mean
Test for a proportion
Difference in means (paired data)
Difference in means (two independent samples)
Difference in proportions
Normal distribution
Correlation
Simple linear regression
Multiple regression
Two-way table (chi-square test)
ANOVA for difference in means
Two-way ANOVA for means
116
A. Researchers were commissioned by the Violence In Children's Television Investigative
Monitors (VICTIM) to study the frequency of depictions of violent acts in Saturday morning TV
fare. They selected a random sample of 40 shows that aired during this time period over a 12week period. Suppose 28 of the 40 shows in the sample were judged to contain scenes depicting
overtly violent acts. How should they use this information to make a statement about the
population of all Saturday morning TV shows?
B. In one of his adventures, Sherlock Holmes found footprints made by the criminal at the scene
of a crime and measured the distance between them. After sampling many people, measuring
their height and length of stride, he confidently announced that he could predict the height of the
suspect. How?
C. Anthropologists have found two burial mounds in the same region. They know several tribes
lived in the region and that the tribes have been classified according to different lengths of skulls.
They measure a random sample of skulls found in each burial mound and wish to determine if
the two mounds were made by different tribes. (p-value = 0.0082)
D. The Career Planning Office is interested in seniors' plans and how they might relate to their
majors. A large number of students are surveyed and classified according to their MAJOR
(Natural Science, Social Science, Humanities) and FUTURE plans (Graduate School, Job,
Undecided). Are the type of major and future plans related? (p-value = 0.047)
E. Sophomore Magazine asked a random sample of 15 year olds if they were sexually active (yes
or no). They would like to see if there is a difference in the responses between boys and girls.
(p-value = 0.029)
F. Every week during the Vietnam War, a body count (number of enemy killed) was reported by
each army unit. The last digits of these numbers should be fairly random. However, suspicions
arose that the counts might have been fabricated. To test this, a large random sample of body
count figures was examined and the frequency with which the last digit was a 0 or a 5 was
recorded. Psychologists have shown that people making up their own random numbers will use
these digits less often than random chance would suggest (i.e., 103 sounds like a more “real”
count than 100). If the data were authentic counts, the proportion of numbers ending in 0 or 5
should be about 0.20. (p-value = 0.002)
G. The Hawaiian Planters Association is developing three new strains of pineapple (call them A,
B, and C) to yield pulp with higher sugar content. Twenty plants of each variety (60 plants in all)
are randomly distributed into a two-acre field. After harvesting, the resulting pineapples are
measured for sugar content and the yields are recorded for each strain. Are there significant
differences in average sugar content between the three strains? (p-value = 0.987)
ITEM 29
Some of the statistical inference techniques we have studied include:
117
A.
B.
C.
D.
E.
F.
G.
H.
One-sample z-procedures for a proportion
Two-sample z-procedures for comparing proportions
One-sample t-procedures for a mean
Two-sample t-procedures for comparing means
Paired-sample t-procedures
Chi-square procedures for two-way tables
ANOVA procedures
Linear regression procedures
For each of the following research questions, indicate (by letter) the appropriate statistical
inference procedure for investigating the question.57
1. Economists compared starting salaries of new employees across three different groups: those
with graduate degrees, those with only bachelor's degrees, and those with no higher education
degrees.
2. A researcher investigated whether laughter increases blood flow by having subjects watch a
humorous movie and a stressful movie, randomly deciding which movie the subject would see
first, measuring the blood flow through the person's blood vessels while watching the movie.
3. Student researchers investigated whether balsa wood is less elastic after it has been immersed
in water. They took 44 pieces of balsa wood and randomly assigned half to be immersed in
water and the other half not to be. They measured the elasticity by seeing how far (in inches) the
piece of wood would project a dime into the air.
4. Do more than two-thirds of students at a particular university have at least one class on
Fridays during this term?
5. Are people more likely to fill in the missing letter in F A I _ with an L if they are given a red
pen rather than a blue pen?
6. Is there an association between a college student's level of drinking alcohol (classified as none,
some, or considerable) and her/his residence situation (classified as living on-campus, offcampus with parents, or off-campus but not with parents)?
7. A researcher used data from the American Time Use Survey (ATUS) to investigate whether
high school math teachers tend to spend more time working per day than high school history
teachers.
8. Biologists recorded the frequency of a cricket's chirps (in chirps per minute) and also the
temperature (in degrees Fahrenheit) when the cricket measurement was recorded. They
investigated whether chirp frequency is a significant predictor of temperature.
57
The list of methods or examples can be shortened.
118
ITEM 30
How accurate are radon detectors sold to homeowners? To answer this question, university
researchers placed 12 radon detectors in a chamber that exposed them to 105 picocuries per liter
of radon. The detector readings found are below, along with some descriptive statistics.58
91.9 97.8 111.4 122.3 105.4 95.0
103.8 99.6 96.6 119.3 104.8 101.7
Variable
readings
N Mean Median TrMean StDev SEMean Minimum Q1 Q3
12 104.13 102.75 103.51
9.40 2.71
122.30 96.90 109.90
1. Is there convincing evidence that the mean 20 readings of all detectors of this type differs from
the true value of 105? Perform the appropriate hypothesis test with alpha = 0.05.
2. Explain what a Type I error associated with this situation would be.
3. Explain what a Type II error associated with this situation would be.
4. What is the probability of a Type II error if the reading of the detectors is too low by 5
picocuries (really 100 when it should read 105)?
ITEM 31
According to a U.S. Food and Drug Administration (FDA) study, a cup of coffee contains an
average of 115 mg of caffeine, with the amount per cup ranging from 60 to 180 mg depending on
the brewing method. Suppose you want to repeat the FDA study to obtain an estimate of the
mean caffeine content to within 5 mg with 95% using your favorite brewing method. How many
cups of coffee must you brew to be 95% confident? In problems such as this, we can estimate the
standard deviation of the population to be 1/4 of the range.
ITEM 32
An internet company is planning to test which of two online ad campaigns is more effective in
generating clicks on their site. Outline the design of an experiment you would use to achieve this
goal. Assume you have money to place 500 ads for each of the two possible campaigns.
ITEM 33
A study of iron deficiency among infants compared samples of infants following different
feeding regimens. One group contained breast-fed infants, while the children in another group
were fed a standard baby formula without any iron supplements.
A graphical display indicated that the blood hemoglobin levels in children (both breast-fed and
formula-fed) are approximately normally distributed in each group. Here are the summary results
on blood hemoglobin levels at 12 months of age:
Group
Breast-fed
Sample size
230
Sample mean
13.3
Sample SD
1.7
58
This item might be improved by providing more output (e.g., 95% confidence interval) to allow students to tackle it without calculation or use
of a table.
119
Formula
230
12.4
1.8
The two-sample t-test yielded a test statistic of 5.51 with 458 degrees of freedom. This is
associated with a two-sided p-value that was less than 0.0001.
Interpret the results from the test statistic and p-value that are provided. Be sure to report the
observed difference in groups in the context of the problem.
ITEM 34
A group of physicians subjected polygraph testing to the same careful testing given to medical
diagnostic tests. They found that if 1,000 people were subjected to the polygraph and 500 told
the truth and 500 lied, the polygraph would indicate that approximately 185 of the truth-tellers
were liars and 120 of the liars were truth-tellers. In the application of the polygraph test, an
individual is presumed to be a truth-teller until indicated that s/he is a liar. What is a Type I error
in the context of this problem? What is the probability of a Type I error in the context of this
problem? What is a Type II error in the context of this problem? What is the probability of a
Type II error in the context of this problem?
ITEM 35
Audiologists recently developed a rehabilitation program for hearing-impaired patients in a
Canadian program for senior citizens. A simple random sample of the 30 residents of a
particular senior citizens home and the seniors were diagnosed for degree and type of
sensorineural hearing loss which was coded as follows: 1 = hear within normal limits, 2 = highfrequency hearing loss, 3 = mild loss, 4 = mild-to-moderate loss, 5 = moderate loss, 6 =
moderate-to-severe loss, and 7 = severe-to-profound loss. The data are as follows:
6 7 1 1 2 6 4 6 4 2 5 2 5 1 5
4 6 6 5 5 5 2 5 3 6 4 6 6 4 2
1. Create a boxplot of the data.
2. Write a brief description of the distribution of the data.
3. Find a 95% confidence interval for the mean hearing loss of senior citizens in this Canadian
program. The mean and standard deviation of the above data are 4.2 and 1.808, respectively.
Interpret the interval.
ITEM 36
A utility company was interested in knowing if agricultural customers would use less electricity
during peak hours if their rates were different during those hours. Customers were randomly
assigned to continue to get standard rates or to receive the time-of-day structure. Special meters
were attached that recorded usage during peak and off-peak hours; the technician who read the
meter did not know what rate structure each customer had.
1. Is this an observational study or experiment? Defend your answer.
2. What are the explanatory and response variables?
3. Identify a potential confounding variable in this work.
4. Is this a matched-pair design? Defend your answer.
120
ITEM 37
At the beginning of the semester, we measured the width of a page in our statistics book two
times. Below is the scatterplot of the first measurement vs. the second measurement.
1. Describe the relationship between the variables.
2. What effect does the starred point have on the correlation coefficient? That is, if the starred
point were removed, how would the correlation coefficient change, if at all?
ITEM 38
A study in the Journal of Leisure Research investigated the relationship between academic
performance and leisure activities. Each in a sample of 159 high-school students was asked to
state how many leisure activities they participated in weekly. From the list, activities that
involved reading, writing, or arithmetic were labeled “academic leisure activities.” Some of the
results are in the table below:
GPA
Number of leisure activities
Number of academic leisure activities
Mean
2.96
12.38
2.77
Standard Deviation
0.71
5.07
1.97
Based on these numbers (and knowing that the GPA is a value between 0 and 4 and the number
of activities cannot be negative), discuss the potential skewness of each of the above variables.
ITEM 39
A random sample of 200 mothers and a separate random sample of 200 fathers were taken. The
age of the mother when she had her first child and the age of the father when he had his first
child were recorded.
121
1. Describe the data for the mothers' age.
2. Describe the data for the fathers' age.
3. Compare the distributions.
4. A suggestion is made to check the correlation between the ages if we wish to compare the two
populations. Is this a good suggestion? Why or why not?
ITEM 40
When conducting a randomized experiment, the original randomization of units to treatment
groups breaks the association between
1. the explanatory variable and the response variable.
2. the explanatory variable and confounding variables.
3. the response variable and confounding variables.
ITEM 41
When conducting a randomization test, the simulated re-randomization of units to treatment
groups breaks the association between
1. the explanatory variable and the response variable.
2. the explanatory variable and confounding variables.
3. the response variable and confounding variables.
122
ITEM 42
For each of the following, circle your answer to indicate whether the quantity can NEVER be
negative or can SOMETIMES be negative:
1. z-score
2. Probability
3. Test statistic
4. Sample proportion
5. Standard deviation
6. Inter-quartile range
7. Standard error
8. p-value
9. Slope coefficient
10. Correlation coefficient
SOMETIMES
SOMETIMES
SOMETIMES
SOMETIMES
SOMETIMES
SOMETIMES
SOMETIMES
SOMETIMES
SOMETIMES
SOMETIMES
NEVER
NEVER
NEVER
NEVER
NEVER
NEVER
NEVER
NEVER
NEVER
NEVER
ITEM 43
A high school statistics class wants to estimate the average number of chocolate chips in a
generic brand of chocolate chip cookies. They collect a random sample of cookies, count the
chips in each cookie, and calculate a 95% confidence interval for the average number of chips
per cookie (18.6 to 21.3). Indicate if each is VALID or INVALID.59
1. We are 95% confident that the confidence interval of 18.6 to 21.3 includes the true average
number of chocolate chips per cookie.
VALID
INVALID
2. We are 95% confident that each cookie for this brand has approximately 18.6 to 21.3
chocolate chips.
VALID
INVALID
3. We expect 95% of the cookies to have between 18.6 and 21.3 chocolate chips.
VALID
INVALID
ITEM 44
Consider an observational study of the effects of second-hand smoke on health in which we want
to compare non-smokers (i) who live with a smoker to (ii) those who do not live with a smoker.
There are two ways in which independence is relevant in the sampling and data collection
process. (a) Give an example in which one type of independence is met but the other is
not; (b) give an example in which the other type of independence is met but the first is not.
ITEM 45
A terse report of a statistical test is given below:
The P-value for a hypothesis test with hypotheses H0: µ = 3
versus HA: µ ≠ 3 is 0.04.
Critique the following responses for clarity, completeness and correctness.
59
Multiple True/False items of this sort can provide very useful information. If there is a single correct understanding for a statistical concept, but
several known misunderstandings for the same concept, a multiple T/F item can provide information on whether or not a student correctly
recognizes each of the misunderstandings as false or invalid.
123
1. This means that the probability of getting our test statistic is 0.04.
2. This means that the probability of getting a test statistic at least as extreme as ours is 0.04.
3. This means that if the null hypothesis is true, the probability of getting a test statistics at least
as extreme as ours is 0.04
4. This means that if the null hypothesis is true, the probability of getting a test statistic less than
or equal to the one we got is 0.04
5. This means that it is very unlikely that the result that was used to compute this P-value would
have happened by pure chance alone, assuming that H0 is true. Therefore we could conclude that
the evidence is against the Null Hypothesis, and H0 is probably not true.
6. The sentence means that assuming the population average is equal to three, the likelihood of
getting an average as large as or larger than we got for our sample is about 4 percent.
7. The p-value is the probability that the data will be as extreme or more extreme as the alternate
hypothesis suggests.
ITEM 46
Explain what the following sentence means:
The interval (2.25, 2.75) is a 99% confidence interval for the mean
GPA of UT students having between 45 and 60 credit hours.
Critique the following responses for clarity and correctness.
1. A 99% confidence interval is used to show that 99% of the time when you pick a sample from
the population (students having between 45 and 60 credit hours) you will find a mean GPA in the
interval (2.25, 2.75).
2. There is a 99% chance that 2.25 ≤ µ ≤ 2.75.
3. This means that if we took many, many simple random samples and constructed a confidence
interval based on each sample, 99% of the resulting confidence intervals would contain the true
mean.
ITEM 47
For each part, draw a scatterplot satisfying the conditions given, or else explain why the
conditions are impossible:
1. Regression line has small positive slope and correlation is high and positive.
2. Regression line has large positive slope and correlation is high and positive.
3. Regression line has small positive slope and correlation is low and positive.
124
4. Regression line has large positive slope and correlation is low and positive.
5. Regression line has positive slope and correlation is negative.
ITEM 48
Rosiglitazone is the active ingredient in the controversial Type 2 diabetes medicine Avandia and
has been linked to an increased risk of serious cardiovascular problems such as stroke, heart
failure, and death. A common alternative treatment is pioglitazone, the active ingredient in a
diabetes medicine called Actos. In a nationwide retrospective observational study of 227,571
Medicare beneficiaries aged 65 years or older, it was found that 2,593 of the 67,593 patients
using rosiglitazone and 5,386 of the 159,978 using pioglitazone had serious cardiovascular
problems. These data are summarized in the contingency table below.
Treatment
Rosiglitazone
Pioglitazone
Total
Cardiovascular problems
Yes
No
2,593
65,000
5,386
154,592
7,979
219,592
Total
67,593
159,978
227,571
Determine if each of the following statements is true or false. If false, explain why. Be careful:
The reasoning may be wrong even if the statement's conclusion is correct. In such cases, the
statement should be considered false.
1. Since more patients on pioglitazone had cardiovascular problems (5,386 vs. 2,593), we can
conclude that the rate of cardiovascular problems for those on a pioglitazone treatment is higher.
2. The data suggest that diabetic patients who are taking rosiglitazone are more likely to have
cardiovascular problems since the rate of incidence was (2,593 / 67,593 = 0.038) 3.8% for
patients on this treatment, while it was only (5,386 / 159,978 = 0.034) 3.4% for patients on
pioglitazone.
3. The fact that the rate of incidence is higher for the rosiglitazone group proves that
rosiglitazone causes serious cardiovascular problems.
4. Based on the information provided so far, we cannot tell if the difference between the rates of
incidences is due to a relationship between the two variables or due to chance.
The next several items are based on simulation (resampling) methods.
ITEM 49
Rosiglitazone is the active ingredient in the controversial Type 2 diabetes medicine Avandia and
has been linked to an increased risk of serious cardiovascular problems such as stroke, heart
failure, and death. A common alternative treatment is pioglitazone, the active ingredient in a
diabetes medicine called Actos.
125
A randomized study compared the rates of serious cardiovascular problems for diabetic patients
on rosiglitazone and pioglitazone treatments. The table below summarizes the results of the
study.
Treatment
Rosiglitazone
Pioglitazone
Total
Cardiovascular problems
Yes
No
2,593
65,000
5,386
154,592
7,979
219,592
Total
67,593
159,978
227,571
1. What proportion of all patients had cardiovascular problems?
2. If the type of treatment and having cardiovascular problems were independent (null
hypothesis), about how many patients in the rosiglitazone group would we expect to have had
cardiovascular problems?
3. We can investigate the relationship between outcome and treatment in this study using a
randomization technique. While in reality we would carry out the simulations required for
randomization using statistical software, suppose we actually simulate using index cards. In
order to simulate from the null hypothesis, which states that the outcomes were independent of
the treatment, we write whether or not each patient had a cardiovascular problem on cards,
shuffle all the cards together, and then deal them into two groups of size 67,593 and 159,978. We
repeat this simulation 10,000 times and each time record the number of people in the
rosiglitazone group who had cardiovascular problems. Below is a relative frequency histogram
of these counts.
4. What are the claims being tested?
5. Compared to the number calculated in the second part, which would provide more support for
the alternative hypothesis, more or fewer patients with cardiovascular problems in the
rosiglitazone group?
6. What do the simulation results suggest about the relationship between taking rosiglitazone and
having cardiovascular problems in diabetic patients?
126
ITEM 50
The Stanford Heart Transplant Study was a randomized trial of a new medical intervention. Of
the 34 patients in the control group, 4 were alive at the end of the study. Of the 69 patients in the
treatment group, 24 were alive. The contingency table below summarizes these results.
Outcome
Alive
Dead
Total
Group
Control
4
30
34
Treatment
24
45
69
Total
28
75
103
1. What proportion of patients in the treatment group and what proportion of patients in the
control group died?
2. One approach for investigating whether or not the treatment is effective is to use a
randomization technique.
2.1 What are the claims being tested? Use correct null and alternative hypothesis notation
2.2 The steps below describes the set up for such approach, if we were to do it without using
statistical software. Fill in the blanks with a number or phrase, whichever is appropriate.
• We write alive on _______ cards representing patients who were alive at the end of the
study, and dead on ________ cards representing patients who were not.
127
•
•
•
•
Then, we shuffle these cards and split them into two groups: one group of size
_________ representing treatment, and another group of size __________ representing
control.
We calculate the difference between the proportion of dead cards in the treatment and
control groups (treatment - control) and record this value. We repeat this many times to
build a distribution centered at ____________.
Lastly, we calculate the fraction of simulations where the simulated differences in
proportions are ________.
If this fraction is low, we conclude that it is unlikely to have observed such an outcome
by chance and that the null hypothesis should be rejected in favor of the alternative.
2.3 What do the simulation results shown below suggest about the effectiveness of the transplant
program?
ITEM 51
Researchers studying the effect of antibiotic treatment compared to symptomatic treatment for
acute sinusitis randomly assigned 166 adults diagnosed with sinusitis into two groups.
Participants in the antibiotic group received a 10-day course of an antibiotic, and the rest
received symptomatic treatments as a placebo. These pills had the same taste and packaging as
the antibiotic. At the end of the 10-day period patients were asked if they experienced
improvement in symptoms since the beginning of the study. The distribution of responses is
summarized below.
Treatment
Antibiotic
Placebo
Total
Self-reported
improvement in symptoms
Yes
No
66
19
65
16
131
35
Total
85
81
166
1. What type of a study is this?
2. Does this study make use of blinding? Justify your answer.
128
3. Compute the difference in the proportions of patients who self-reported an improvement in
symptoms in the two groups: p̂antibiotic − p̂ placebo .
4. At first glance, does antibiotic or placebo appear to be more effective for the treatment of
sinusitis? Explain your reasoning using appropriate statistics.
5. There are two competing claims that this study is used to compare: the null hypothesis that the
antibiotic has no impact and the alternative hypothesis that it has an impact. Write out these
competing claims in easy-to-understand language and in the context of the application.
6. Below is a histogram of simulation results computed under the null hypothesis. In each
simulation, the summary value reported was the number of patients who received antibiotics and
self-reported an improvement in symptoms. Write a conclusion for the hypothesis test in plain
language. (Hint: Does the value observed in the study, 66, seem unusual in this distribution
generated under the null hypothesis?)
Examples of Assessments for Presentations and Projects
Projects and presentations are an increasingly common component of introductory statistics
courses.60
Projects provide an opportunity for students to learn statistics by doing statistics. They
demonstrate that statistical practice includes formulating a statistical question, designing a plan
60
Halvorsen’s ICOTS 2010 paper (http://iase-web.org/documents/papers/icots8/ICOTS8_4G3_HALVORSEN.pdf) provides motivation for the
use of projects as well as details of specific deliverables.
129
for collecting relevant data, using appropriate statistical methods for analyzing the data, and
presenting results in a public setting such as a poster, oral presentation, or a paper (Halvorsen
2010).
Students have the opportunity to develop statistical questions that arise from broader research
questions, to design data analysis plans, and to communicate results.
We provide a basic rubric for presentations and projects along with a sample numeric grading
scheme.
Core Competency
Computation
Perform computations
Needs Improvement
Computations contain
errors and extraneous
code
Basic
Computations are correct but
contain
extraneous/unnecessary
computations
Analysis appropriate, but
incomplete, or not important
features and assumptions not
made explicit
Surpassed
Computations are correct
and properly identified and
labeled
Analysis
Choose and carry out
analysis appropriate for
data and context
Choice of analysis is
overly simplistic,
irrelevant, or missing key
component
Synthesis
Identify key features of
the analysis, and
interpret results
(including context)
Visual presentation
Communicate findings
graphically clearly,
precisely, and
concisely
Verbal
Communicate findings
in writing clearly,
precisely, and
concisely
Conclusions are missing,
incorrect, or not made
based on results of
analysis
Conclusions reasonable, but is
partially correct or partially
complete
Make relevant conclusions
explicitly connected to
analysis and to context
Inappropriate choice of
plots; poorly labeled
plots; plots missing
Plots convey information
correctly but lack context for
interpretation
Plots convey information
correctly with
adequate/appropriate
reference information
Explanation is illogical,
incorrect, or incoherent
Explanation is partially correct
but incomplete or
unconvincing
Explanation is correct,
complete, and convincing
Analysis appropriate,
complete, advanced,
relevant, and informative
If needed, the competencies can be converted into a numeric score.
One might begin by giving a score of 85 for achieving basic competency in all 5 categories. Then
we add to this score for competencies that surpass the basic level and subtract for those that need
improvement. Three points might be added (subtracted) for each of the first three competencies
that have surpassed the basic (need improvement), with four points added (subtracted) for the
fourth competency that is surpassed (needs improvement) and five points for the fifth
competency. In other words, it is increasingly challenging to surpass the basic competency, and
it is increasingly problematic to not achieve basic competency. For example, if all five
competencies are rated “surpassed,” the score is 85 + 3*3 +4 + 5 = 100; if 4 competencies are
rated “surpassed” and the fifth is “basic,” then the score is 85 + 3*3 +4 = 95; and for 3
“surpassed,” 1 “needs improvement,” and 1 “basic,” the score is 85 + 3*3 - 3 = 91. If a
competency is missing, then 15 points are subtracted regardless of how many competencies are
categorized as needing improvement.
130
APPENDIX
APPENDIX F:
F: Learning Environments
Instructors work in a variety of settings, and some readers may question whether they can adopt
the GAISE recommendations. Different classroom situations have areas of greater and lesser
challenges in the implementation of the recommendations. This appendix provides examples of
ways to apply the recommendations in different environments. Five common instructional
conditions explored are
•
•
•
•
•
face-to-face, both large and small class sizes
flipped (inverted) classes
distance learning
cooperative learning
limited technology
The purpose of this appendix is to provide research references and a few inspiring examples for
implementing GAISE teaching in courses where one or more of the recommendations for
teaching appear difficult to employ.
Face-to-Face Courses
Whether instruction is in a classroom or an individual tutoring setting, instruction in statistics has
primarily been in a face-to-face format. While times are changing and other approaches are now
available, the majority of college and university teaching of statistics still occurs in a face-to-face
environment. In these college settings, the class size ranges from small to medium to large and
to what some would even call very (or extremely) large. In this appendix, we illustrate how to
incorporate the GAISE recommendations in teaching situations made complex by class size. For
example, some have questioned the feasibility of active learning in a large class setting. Others
have found that with very small classes a simulation completed with manipulatives by the
students in the class might not demonstrate the desired principle.
Small Classes:
Collecting data from students during class is suggested as a way to foster active learning and
integrate real data with a context and purpose. Classes with low enrollment, however, cannot
collect enough data to be used in the same ways that larger classes can.
Example #1: Physical Exploration
When an active, concrete illustration (e.g., die rolling, card shuffling) is desirable prior to a
computer simulation that demonstrates a concept, individual students can repeat the task more
than once to help generate additional real data. Another alternative is to have the students
complete a process and record the result just once in the classroom in order to understand the
process, and then to use technology-based simulations, such as applets, to repeat the simulation
131
many times quickly. Alternatively, the teacher could prime the pump with a simulated data set
and then add class data to those starter data.
Example #2: Project Data from the Class
One way to overcome the issue of collecting a large enough sample for use in a class-focused
project is to keep records of the data collected over several semesters. Another option is to
collect and share data with colleagues across multiple sections of the course. Beginning with the
data collected from the class members, a conversation of the limitations of the small sample size
can motivate additional data collection from a larger sample of non-classmates.
To teach statistical thinking, focus on conceptual understanding, or foster active learning, peerto-peer interactions are often an integral part of the educational experience. A small class
necessarily means fewer peers to interact with, creating challenges for instructors.
Example #3: Cooperative Groups
Some faculty find that using cooperative groups is a great strategy for teaching statistics (see the
last section of this appendix and Appendix C: Activities, Projects, Data). Small classes limit the
size of the groups and/or the number of groups. Pairing of students after initial dyad discussions
provides an opportunity to leverage collaboration. Although is tempting in a small class to let
individual students work to their strengths, rotating the group member’s roles ensures all students
have opportunities to lead, record, present, etc. Distributing responsibility to individual students
for presentation of some of the “light” topics in the course can nurture the sense of ownership for
learning among the classmates.
Example #4: Student Presentation of the Results
Fewer students allow time for students to report results from their small group (or individual)
work to the entire class. Peer review/evaluation of such presentations offers additional
interaction, whether written or verbal, immediate or after class.
Large Classes:
While large classes provide a great opportunity for collecting large data sets, they produce their
own set of challenges. For example, many excuses have been heard to not foster active learning
through the use of groups in large classes: “the chairs do not move,” “I won’t be able to talk to
all the groups,” “it will be too loud,” etc. Carbone (1998) indicates that active/cooperative
learning can be effective in large classes as well as small ones and provides suggestions to foster
active learning in large classes. For very large classes, an assistant, who might even be an
advanced student, could be helpful for group supervision (Davidson 1990). In some cases there
may be an opportunity to break a large statistics course into separate smaller lab or discussion
sections in which group work and activities could be used.
Gelman and Nolan (2002) report that with careful selection, activities can be used successfully in
large statistics classes and strongly encourage group work to promote student learning. In
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particular, they suggest that when selecting activities for large classes, choose those in which the
majority of students remain seated and a limited number of students go to the board or make a
presentation to the class.
Regardless of the class size, involving students in the course is important. Gelman and Nolan
(2002) provide an example of “Active Homework”: Throughout the semester, they suggest
assigning pairs of students to go to the library to find data that is needed for class or brought up
in a class discussion. For a small class, by the end of the semester, the entire class could have
this experience. Another approach to this same activity is to have students find data from the
web to bring to class.
Example #1: Working with Partners in Positive, Productive Ways
A modification of the think-pair-share method that has been recommended for large classes by
Blumberg (2015) can be remembered with the acronym FSLC. These letters help the students
remember to Formulate the answer on their own first, then Share it with a partner. The
acronym specifically encourages important partner behaviors, and teachers are encouraged to not
omit the last two steps of the process which are to ensure that students Listen carefully to the
answer of their partner and then Create a new answer that uses both partner’s information in a
manner so that the new answer is better than each of the individual answers.
Example #2: Cooperative Groups
In large, tiered lecture halls with fixed chairs, students may find it logistically easier to work in
pairs instead of groups. The instructor can use a think-pair-share structure and randomly call on
a student to report the thinking for their group. Asking the question and then using a random
number generator to determine the student to be selected can help keep students in a large class
alert. Sampling with replacement ensures students know they could be called on again at any
time.
Example #3: Data Collection Using Class Polling
Zullo and Cline’s book Teaching Mathematics with Classroom Voting: With and Without
Clickers includes three chapters on using clickers in introductory statistics courses. Examples
include lesson plans for box plots, hypothesis testing, confidence intervals, and data collection.
Furthermore, the text describes how to select lessons that are good for using classroom voting
and how to use these approaches for developing conceptual understanding. Specific examples
can be found in Appendix D: Examples of Using Technology.
Example #4: Using Online Surveys to Maximize Class Time
With the ever increasing number of free or low-cost online tools for developing surveys,
professors can maximize class time by setting up online surveys to collect data either in (via a
mobile device such as a phone) or out of class as an efficient means of data collection. The
article by Taylor and Doehler (2014) includes activity ideas and implementation details for using
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survey software for data collection in introductory statistics. Specific examples can be found in
Appendix D: Examples of Using Technology.
References/Resources:
Blumberg, P. (2008), Developing Learner-centered Teaching: A Practical Guide for Faculty.
San Francisco: Jossey-Bass.
Blumberg, P. (2015), “Student Participation/Active Learning,” University of the Sciences’
Teaching and Learning Center. Available at
http://www.usciences.edu/teaching/tips/spal.shtml#within
Carbone, E. (1998), Teaching Large Classes: Tools and Strategies, SAGE Publications.
Davidson, N. (1990), “Small-group Cooperative Learning in Mathematics,” Teaching and
Learning Mathematics in the 1990s. The NCTM Yearbook, 52-61.
Gelman, A., and Nolan, D. (2002), Teaching Statistics: A Bag of Tricks, Oxford: Oxford
University Press.
Taylor, L., and Doehler, K. (2014), “Using Online Surveys to Promote and Assess Learning,”
Teaching Statistics, 36, 34-40.
Zullo, H., and Cline, K. (2012), Teaching Mathematics with Classroom Voting: With and
Without Clickers, MAA Notes [Washington, DC]: MAA, Mathematical Association of America.
Flipped (Inverted) Classes
With audio, video, and even graphical materials easier to develop and make available online,
opportunities for efficiently sharing materials with students are expanding. Some faculty are
utilizing those types of technology to restructure in-class and out of-class learning environments.
Faculty use technology to provide online lectures for students to listen to and learn from outside
of class. Now they have evolved into videos of the teaching providing lecture-type instruction or
of slides with a voiceover which uses animations to help students visualize a concept. In some
cases, students watch these videos prior to class. The students then come to the classroom ready
to engage in active learning to solve more sophisticated problems than would be easy to solve at
home or in isolation. This type of learning structure has been called the "flipped" or "inverted"
classroom. The inverted classroom model offers multiple opportunities, both in and out of the
classroom, for helping students develop statistical thinking and conceptual understanding.
Example 1: Out-of-class Videos and In-class Problem Solving Sections
Lape et al. (2014) found that students who watch videos outside of class and use class time in
Engineering and Mathematics for problem solving sessions believe that the class time helped
them learn the concepts more than students in the corresponding traditionally taught courses.
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Example 2: Motivating Reading
Wilson (2013) provides incentives for reading the textbook outside of class by giving “reading
quizzes,” and while only around 60% of the students rated the readings as helpful, they did
significantly increase the amount of reading they did for the course as compared to when the
course was taught in the traditional lecture approach. Wilson used a model where the lecture
material was moved outside of class and the homework, which was presented as application-type
activities that could be done individually or in groups, was completed during the scheduled class
time. She found for both student-reported learning and for student final exam grades that the
flipped classroom teaching model was significantly better than the traditional model. Thus, in
terms of the GAISE recommendations, instructors could focus reading and the corresponding
quizzes on conceptual understanding. Furthermore, using the flipped classroom approach
including reading quizzes on concepts could, without loss of content, make more time during the
class period for engaging students in significant active learning activities (See also Appendix C:
Activities, Projects, Data.)
Example 3: Informed Classroom Instruction
Strayer (2014) recommends teachers convey information to students outside of class to gain a
response from the students prior to coming to the class. These responses should be viewed by
teachers before class to better inform them how to teach the class during the face-to-face time
with the students. It is particularly helpful if the teacher can construct the task to reveal students’
conceptions as well as their misconceptions. Building on the knowledge gained from the out-ofclass material, the teacher can be prepared to efficiently structure class discussions to extend the
students’ knowledge. While the task for Strayer’s research was an algebra lesson for pre-service
teachers, the lessons learned are transferable to flipped introductory statistics courses.
References/Resources:
Bishop, J., and Verleger, M. (2013), “The Flipped Classroom: A Survey of the Research,” in
120th ASEE Annual Conference and Exposition.
Flipped Learning Network. Available at http://fln.schoolwires.net/Page/1
Lape, N., Levy, R., Yong, D. H., Haushalter, K. A., Eddy, R., and Hankel, N. (2014), “Probing
the Inverted Classroom: A Controlled Study of Teaching and Learning Outcomes in
Undergraduate Engineering and Mathematics,” Paper presented at 2014 ASEE Annual
Conference, Indianapolis, Indiana.
Rayens, W. (2012), “Teaching Statistical Concepts in an Inverted Classroom,” University of
Kentucky. Available at http://www.causeweb.org/webinar/teaching/2012-01/.
Strayer, J. (2012), “How Learning in an Inverted Classroom Influences Cooperation, Innovation
and Task Orientation,” Learning Environments Research, 15, 171-193.
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Wilson, S. G. (2013), Teaching of psychology: The flipped class: A method to address the
challenges of an undergraduate statistics course. Lawrence Erlbaum Associates, Inc.
Distance Learning
As technology continues to advance, the use of online instruction to teach statistics has also
evolved. The instruction in the online course can be asynchronous, synchronous or partially
synchronous. Some online courses are broadcast live to an audience that can both see and hear
the professor and the teacher can see and hear all of the students in remote locations at the same
time. Since an online class is sometimes a result of students having work schedules which make
meeting face-to-face difficult, the online class can also take on an asynchronous format where
students watch videos of the instructor or the textbook author on their own time. Another format
for the online course is partially synchronous in which there is a combination of face-to-face
meetings and online instruction. These courses may have different names such as hybrid,
blended, or web-enhanced, and they may have different percentages of time spent in the online
or the face-to-face environment. Today, there are Massive Open Online Courses (MOOCs)
which provide opportunities for learning to tens of thousands of people. Moreover, the MOOCs
can be led by an instructor with a set schedule for completing course materials or can be
completely self-paced.
Complete definitions and best practices for each of these learning environments can be found at
the Hidden Curriculum webpage (Abbott 2014). Common themes for best practices include
maximizing the strengths of each approach to foster interaction between students for discussions
and collaborations regarding learning. For the partially synchronous environment, similar to the
flipped classroom environment, instructors should carefully consider how to use the in-class time
to maximize learning based on the goals of the course.
As faculty design online courses based on the GAISE recommendations, the following examples
about technology might be useful in making decisions about the learning environment in which
different content is delivered.
Example #1: Data Collection
Teachers can integrate real data with a context and a purpose in distance learning environments
by using online surveys for collecting data which can be shared with the entire class. This type
of data collection about the students can create interest and foster interactions.
Example #2: Discussion Boards
Discussion boards can be used to have students describe how they would use statistics in their
major. This can help students connect with other students in their major while they are learning
more about applications of statistics in the real world. Critique of journalistic efforts to report
scientific research can engender online conversation even asynchronously. The instructor can set
up specific “question and answer” assignments where the students can use the discussion board
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to help each other better understand the material. Discussing the choice of analytical tool – by
students for their coursework or by researchers whose reports are being critiqued – provides
opportunity for statistical thinking, focusing on concepts, using technology, and multivariable
thinking.
Example #3: Simulations
The teacher can create short videos demonstrating a simulation using an applet. Then the
students can follow the example in the video to run their own simulations for similar problems,
using technology to explore concepts. (See also Appendix D: Examples of Using Technology.)
Students can be asked to post decision responses telling what they learned from a simulation to
encourage statistical thinking and serve as an assessment to improve and evaluate student
learning.
References/Resources:
Abbott, S. (Ed) (2014), “Hidden curriculum,” The glossary of education reform. Available at
http://edglossary.org/hidden-curriculum
Everson, M. G., and Garfield, J. (2008), “An Innovative Approach to Teaching Online Statistics
Courses,” Technology Innovations in Statistics Education, 2. Available at
http://escholarship.org/uc/item/2v6124xr.
Mills, J. D., and Raju, D. (2011), “Teaching Statistics Online: A Decade’s Review of the
Literature about What Works,” Journal of Statistics Education, 19. Available at
http://www.amstat.org/publications/jse/v19n2/mills.pdf
Mocko, M. (2013), “Selecting Technology to Promote Learning in an Online Introductory
Statistics Course,” Technology Innovations in Statistics Education, 7. Available at
http://escholarship.org/uc/item/596195sg.
Tudor, G. (2006), “Teaching Introductory Statistics Online – Satisfying the Students,” Journal of
Statistics Education, 14. Available at http://www.amstat.org/publications/jse/v14n3/tudor.html
Ward, B. (2004), “The Best of Both Worlds: A Hybrid Statistics Course,” Journal of Statistics
Education, 12. Available at http://www.amstat.org/publications/jse/v12n3/ward.html
Utts, J., Sommer, B., Acredolo, C., Maher, M., and Matthews H. (2003), “A Study Comparing
Traditional and Hybrid Internet-Based Instruction in Introductory Statistics Classes,” Journal of
Statistics Education, 11. Available at http://www.amstat.org/publications/jse/v11n3/utts.html
Cooperative Learning
A cluster of teaching/learning techniques (with a variety of names and purposes) that involve
students working together can provide opportunities for implementing GAISE recommendations
into statistics courses. Team-based (St. Clair and Chihara 2012), student-driven (Sovak 2010),
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cooperative (Garfield 1993) or collaborative (Roseth, Garfield, and Ben-Zvi 2008) learning, and
guided investigations (Bailey, Spence, and Sinn 2013) have nuances as outlined in the given
references, but all come down to opportunities to foster active learning in the classroom and
integrate real data with a context and a purpose, often necessitating the use of technology to
analyze it. The actual tasks assigned to small groups of students might incorporate the remaining
recommendations by focusing on statistical thinking and conceptual understanding.
For institutions or instructors who design entire courses around these types of instruction, we
provide a few more examples in addition to the larger collection in Appendix C: Activities,
Projects, Data.
Example #1 - Histogram Comparisons
Each student is assigned a pair of histograms (out of four such pairs) for which they must
determine which has more variability. They then discuss their reasoning with a partner until
consensus is gained on both pairs of histograms. New partnerships are made and each student
must explain the reasoning to the new partner for both their own and their original partner’s
histograms. In the end, every member of the foursome has four well-reasoned examples for
determining the relative size of variability. Active learning and a conceptual understanding of
variability are inherent in this activity.
Inspired by Roseth, Garfield, and Ben-Zvi (2008).
Example #2 – Coin Distribution
Students bring coins from home (specify pennies, nickels, etc.) and in their groups they sort them
by minting dates, calculating the ages. Several descriptive graphs, tables, or measures might be
made on the small collection before compiling the data from all the groups into the classroom
sample and making further descriptives, perhaps using technology. The use of real data in
practicing the construction of dot plots, histograms, and other graphs brings active learning to
the classroom. This might be a review of earlier descriptive topics and/or serve as a launching
point for whole class discussion of sample size, limitations due to sampling methods, outliers,
and/or informal inference.
Inspired by National Council of Teachers of Mathematics (2014). Principles to Actions:
Ensuring Mathematical Success for All. Reston, Virginia: National Council of Teachers of
Mathematics.
Example #3 – NFL Quarterback Salaries
In general, a jigsaw activity gives different information to different group members so that it
requires cooperation and discussion to fit the pieces together before the final question(s) can be
answered. Determining the best predictor (Pass Completion %, Touchdowns, or Yards per
Game) of quarterback salary through r and r2 can be just such a task. Providing each group
member with one data set to compare to the salary allows each student the practice in calculating
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r and r2. In order to come to consensus on the best predictor; however, comparisons of numbers,
graphs, and appropriate use of vocabulary is required. Follow-up questions can tap statistical
thinking and conceptual understanding in addition to the use of real data, active learning, and
technology that was used to analyze the data. There is also opportunity to address the reality of
multi-variate predictors.
Inspired by STatistics Education Web, http://www.amstat.org/education/STEW/.
References/Resources:
Bailey, B., Spence, D. J., and Sinn, R. (2013), “Implementation of Discovery Projects in
Statistics,” Journal of Statistics Education, 21. Available at
http://www.amstat.org/publications/jse/v21n3/bailey.pdf
[NSF-funded curriculum available at http://faculty.ung.edu/DJSpence/NSF/materials.html]
Garfield, J. (1993), “Teaching Statistics Using Small-Group Cooperative Learning,” Journal of
Statistics Education, 1. Available at http://www.amstat.org/publications/jse/v1n1/garfield.html
Roseth, C. J., Garfield, J. B., and Ben-Zvi, D. (2008), “Collaboration in Learning and Teaching
Statistics,” Journal of Statistics Education, 16. Available at
http://www.amstat.org/publications/jse/v16n1/roseth.html
Sovak, M.M. (2010), The Effect of Student-Driven Projects on the Development of Statistical
Reasoning (Doctoral Dissertation). Retrieved from http://iaseweb.org/Publications.php?p=Dissertations.
St. Clair, K., and Chihara, L. (2012), “Team-Based Learning in a Statistical Literacy Class,”
Journal of Statistics Education, 20. Available at
http://www.amstat.org/publications/jse/v20n1/chihara.pdf
Limited Technology
Technology has had many forms and definitions over the years. Today, certain forms of
technology are considered standard in many introductory statistics courses; however, that
definition of “standard” varies by institution. Some classrooms for teaching statistics have
statistical analysis software and software for visualizing statistical simulations on computers
while other institutions might not have a computer lab large enough to seat an entire statistics
class. Some courses meet in computer labs, while others might have a weekly lab session. At
some schools, the only computer is at the instructor’s station, while at others, students bring their
own devices to class. And, unfortunately, there are schools where students don’t have access to
any technology at all. Even for instances when instructors feels that their classroom
environments might be “technology deprived,” there are still ways to provide instruction which
support the GAISE recommendations.
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Example #1: Teacher Demonstrations
If the course instructor has access to a computer projection system, the teacher can bring a laptop
into the classroom to demonstrate using statistical software to analyze large data sets and provide
an opportunity for students to see that computation is the least important task of a statistician.
Instructors can often receive complementary or discounted statistical analysis software. Many of
these tools include instructional videos to help the student learn how to use the software outside
of teacher instructional time. Teachers can also demonstrate applets which allow students to
quickly observe results of a simulation that would be too time-consuming using physical
manipulatives. Online statistical analysis tools and applets can be found in the statistics
education digital library, CAUSEweb.org, using the advanced search tool. (See Appendix D:
Examples of Using Technology for additional examples.)
After demonstrating how to use statistical software, the teacher can provide the students with a
handout of examples of statistical output for practice at interpreting analysis results. Students
should be able to answer questions on exams interpreting the output of statistical software, such
as the question below.
•
The body temperatures of a random sample of 65 healthy male college students were taken.
Researchers wanted to know if the body temperature of college-age males is different from
the “normal” body temperature of 98.6 degrees Fahrenheit. Use the output from a statistical
software package to test the researcher’s hypothesis at the 5% significance level. Then state
your conclusion in the context of the problem.
Inspired by the ARTIST Assessment Builder, https://apps3.cehd.umn.edu/artist/user/login.asp.
Note: A free registration is required for using the Assessment Builder.
Example #2: Calculators for Statistical Analysis
When statistical software packages are not an option, graphing calculators with pre-programmed
statistical functions can be used to minimize time spent by students on computation and
maximize time spent on conceptual understanding and interpreting the statistical output in the
context of the given problems. In conjunction with the demonstration of statistical software,
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students should understand that calculators are not the technology of practicing statisticians or
researchers from other fields doing data analysis.
Example #3: Physical Manipulatives
Classrooms with limited technology should not be deprived of physical manipulatives or
opportunities to actively engage students in learning statistics. For example, having students
make a “living boxplot” based on student data is a great way to get the students to actually be the
manipulatives and to visualize what it means to have 25% of the data in a given region.
Scheaffer et al. (2004) provide instructions for that and other rich activities which might only
require paper and a ruler to teach statistical thinking, focus on conceptual understanding, and
foster active learning.
References/Resources:
ARTIST Assessment Builder. https://apps3.cehd.umn.edu/artist/user/login.asp. Assessment
Builder FAQ https://apps3.cehd.umn.edu/artist/QA.html.
CAUSEweb.org. The Consortium for the Advancement of Undergraduate Statistics Education
(CAUSE) Digital Library for Statistics Education Resources, Research, and Professional
Development.
Scheaffer, R., Watkins, A., Witmer, J., and Gnanadesikan, M. (2004), Activity-based Statistics,
Instructors Guide, 2nd Ed., revised by Erickson, T. Key College Publishing.
Texas Instruments, TI 84 Activity Central. Statistics: Find Activities that Support your Lessons.
Available at https://education.ti.com/en/84activitycentral/us/Statistics.
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