Preface

Statistics is hot. According to the New York Times on June 20, 2013, statistics is perhaps the most promising, adventurous career option you can choose right now—and it is likely to expand significantly in the future, thanks to the large amounts of information (called big data) available to us in this digital age. Gone is the stereotype of boring (but influential) statistics geeks wearing green eyeshades and pocket protectors. The new reality requires smart, reflective people who have been trained to dip their spoons into the salty ocean of big data, transform those data into something we can consume, and still leave the ocean of data as a vibrant, ever-evolving home for exotic creatures. This book trains you to find and create data, ask tough questions about a data set, interpret the feedback coming from data analysis, and display data in ways that reveal a precise, coherent, data-driven story. Statistical reasoning is not at the cutting edge of information; statistical reasoning is the cutting edge of information.

If you dare to embrace what your professor is teaching you, it will bring you to the brink of personal and social change. You will have to make many decisions about how you think—and that covers, well, your entire life. There are probably some natural boundaries to the benefits of statistical reasoning, such as the power of intuition. But every time we think we have bumped into a boundary, somebody busts through it, wins a Nobel Prize, and challenges the rest of us to become more creative as we learn how to live together on this beautiful planet.

We dare you to love this course.

Trends in Statistics: What’s Coming Next?

Statistics and statistical reasoning are in the midst of profound changes. Here are three important trends:

Trend 1: Visual Displays of Data. On the one hand, Chapter 3 of this text reminds us that there is nothing very new about creating visual displays of data. On the other hand, the entire field has gone topsy-turvy with graphic artists, newspaper editors, journalists, and anyone with an imagination and a computer jumping into the action. Data graphics are the hot new way to search for patterns, tell data-driven stories, and gain new insights from the enormous volumes of information available to us. This trend isn’t coming; it’s here. And the field needs a lot of guidance, without suppressing all that energy and creativity. In short, the field needs smart, hard-working, creative, and visually oriented behavioral scientists.

Trend 2: Bayesian Statistics. The field of statistics is also moving forward by looking backwards! The story of Thomas Bayes, an obscure clergyman born around 1701, demonstrates that some great ideas just won’t go away. Imagine that a ball is thrown onto a square billiard table and that it comes to rest slightly to the left of center. But the ball is removed before we get to see where it landed—so its exact landing place is unknown to us; we can only estimate where it stopped. More balls are then rolled onto the table, each with the same random set of possibilities—and we are only told whether or not each ball has landed to the right or left of the original ball. With each additional piece of feedback, we can slowly come to estimate (with increasing confidence) where the first ball actually landed. By learning from prior experience (called priors in Bayesian statistics), we become slightly less wrong about the first ball’s location every time a new ball is rolled onto the billiard table. The heart of Bayesian reasoning is to gradually rule out what cannot be true, so the process of discovery becomes more exciting with every analysis. The implications are just starting to hit the world of behavioral statistics, and it is difficult to predict where all this excitement will take us next. But this is an impressive outcome for an obscure clergyman whose only mathematical paper was published after his death.

Trend 3: Free Software. Although earning a college degree is pretty expensive, the Internet has created opportunities for particular forms of education to progressively become less expensive. Massive open online courses (MOOCs) are just one of the more obvious efforts. One of your coauthors, Tom, took one MOOC with 80,000 other classmates. He didn’t actually finish the course because early on, he already had gotten what he wanted out of the course and didn’t need to learn how to write a research paper. Kahn Academy online tutorials are another excellent, low-cost (though it costs you time) way to become better educated. A third opportunity is the increase in free statistical programs available online. We introduce one in this book; G*Power is free software that helps researchers determine statistical power and the appropriate sample size. Another is a statistical program simply called R. This is a free, sophisticated, open-source statistical software package; you can download it right now from the R Foundation. R will always be in development because its users are always improving it. As of this writing, R is still not that easy to use but people keep improving it. The future of statistics will probably have free, open-source software that is fairly easy to use.

What’s New in the Third Edition

In this new edition of Statistics for the Behavioral Sciences, we connect students to statistical concepts as efficiently and memorably as possible. We’ve sharpened the focus of the book on the core concepts and introduce each topic with a vivid, real-world example. Our pedagogy first emphasizes mastering concepts, and then gives students multiple step-by-step examples of the process of each statistical method, including the mathematical calculations. The extensive Check Your Learning exercises at the end of each section of the chapter, along with the end-of-chapter exercises and the new LaunchPad Web site, give students lots of opportunities to practice. Indeed, there are close to twice as many exercises in the third edition as in the first. We’ve also clarified our approach by fine-tuning the following features throughout the book.

Before You Go On

Each chapter opens with a Before You Go On section that highlights the concepts students need to have mastered before they move on to the next chapter.

Mastering the Formulas and Mastering the Concepts

Some of the most difficult tasks for students new to statistics are identifying the key points and connecting this new knowledge to what they have covered in previous chapters. The unique Mastering the Formula and Mastering the Concept marginal notes provide students with helpful explanations that identify each formula when it is first introduced and each important concept at its point of relevance. Appendix E, Figure E-1: Choosing the Appropriate Hypothesis Test is a terrific summary that shows students how to apply statistical techniques to their research. It’s the entire text summarized on a single page; students will learn it quickly and use it for the rest of their careers in statistics.

Illustrative, Step-by-Step Examples

The text is filled with real-world examples from a wide variety of sources in the behavioral sciences. We outline statistical techniques in a step-by-step fashion, guiding students through each concept by applying the material creatively and effectively.

SPSS^®

For instructors who integrate SPSS into their course, each chapter includes outlined instructions and screenshots of SPSS output to help students master the program using data from the text.

How It Works—Chapter-Specific Worked-Out Exercises

Many students have anxiety as they approach end-of-chapter exercises. To ease that anxiety, the How It Works section provides students with step-by-step worked-out exercises representative of those they will see at the end of the chapter. This section appears just before the end-of-chapter exercises and acts as a model for the more challenging Applying the Concepts and Putting It All Together questions.

Building Better Graphs Using Excel

A new appendix guides students through the basics of creating a clear, readable graph with Excel. Using an example from the text, students are guided through the steps of creating a graph and then changing Excel’s default choices to meet the criteria for an excellent graph.

Game Design and Practice

Like a computer game that uses repetition and small changes to lift its players to higher levels of achievement, we have designed increasing challenges beginning with confidence-building Check Your Learning sections within each chapter. Many of the more than 1000 exercises available in the text are based on real data, so professors and students can choose from among the most engaging exercises. Students can develop the ability to read, understand, and report statistics used in scientific journals by selecting from four tiers of exercises:

• Clarifying the Concepts questions help students to master the general concepts, the statistical terminology, and the conceptual assumptions of each topic.
• Calculating the Statistics exercises provide students a way to practice making the basic calculations for each formula and statistic.
• Applying the Concepts exercises apply statistical questions to real-world situations across the behavioral sciences and require students to bridge their knowledge of concepts and calculations.
• Putting It All Together exercises ask students both to apply the concepts from the chapter to a real-world situation and to connect the chapter’s concepts to ideas from previous chapters.

Media and Supplements

LaunchPad with LearningCurve Quizzing

A comprehensive Web resource for teaching and learning statistics

LaunchPad combines Worth Publishers’ award-winning media with an innovative platform for easy navigation. For students, it is the ultimate online study guide, with rich interactive tutorials, videos, an e-Book, and the LearningCurve adaptive quizzing system. For instructors, LaunchPad is a full course space where class documents can be posted, quizzes can be easily assigned and graded, and students’ progress can be assessed and recorded. Whether you are looking for the most effective study tools or a robust platform for an online course, LaunchPad is a powerful way to enhance your class.

LaunchPad for Statistics for the Behavioral Sciences, Third Edition, includes all the following resources:

• The LearningCurve quizzing system was designed using the latest findings from learning and memory research. It combines adaptive question selection, immediate and valuable feedback, and a game-like interface to engage students in a learning experience that is unique to them. Each LearningCurve quiz is fully integrated with other resources in LaunchPad through the Personalized Study Plan, so students can review Worth’s library of videos and activities. State-of-the-art question analysis reports allow instructors to track the progress of individual students as well as their class as a whole.
  

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• An interactive e-Book allows students to highlight, bookmark, and make their own notes, just as they would with a printed textbook. Students can use Google-style searching and take advantage of in-text glossary definitions.
• The Statistical Video Series consists of StatClips, StatClips Examples, and Statistically Speaking “Snapshots.” The videos can be used to view animated lecture videos, whiteboard lessons, and documentary-style footage that illustrate key statistical concepts and help students visualize statistics in real-world scenarios.
  • StatClips lecture videos, created and presented by Alan Dabney, PhD, Texas A&M University, are innovative visual tutorials that illustrate key statistical concepts. In 3 to 5 minutes, each StatClips video combines dynamic animation, data sets, and interesting scenarios to help students understand the concepts in an introductory statistics course.
  • In StatClips Examples, Alan Dabney walks students through step-by-step examples related to the StatClips lecture videos to reinforce the concepts through problem solving.
  • SnapShots videos are abbreviated, student-friendly versions of the Statistically Speaking video series, and they bring the world of statistics into the classroom. In the same vein as the successful PBS series Against All Odds: Inside Statistics, Statistically Speaking uses new and updated documentary footage and interviews that show real people using data analysis to make important decisions in their careers and in their daily lives. From business to medicine, from the environment to understanding the census, SnapShots help students see why statistics is important for their careers, and how statistics can be a powerful tool to understand their world.
• Statistical Applets allow students to master statistical concepts by manipulating data. The applets can also be used to solve problems.
• EESEE Case Studies, taken from the Electronic Encyclopedia of Statistical Exercises and Examples, offer students additional applied exercises and examples.
• A data set from the General Social Survey (GSS) gives students access to data from one of the most trusted sources of sociological information. Since 1972, the GSS has collected data that reflect changing opinions and trends in the United States. A number of exercises in the text use GSS data, and this data set allows students to explore further.
• The Assignment Center lets instructors easily construct and administer tests and quizzes from the book’s Test Bank and course materials. The Test Bank includes a subset of questions from the end-of-chapter exercises with algorithmically generated values, so each student can be assigned a unique version of the question. Assignments can be automatically graded, and the results are recorded in a customizable gradebook.

Additional Student Supplements

• SPSS: A User-Friendly Approach by Jeffrey Aspelmeier and Thomas Pierce of Radford University is an accessible introduction to using SPSS. The book uses a proven teaching method, building each section of the text around the storyline from a popular cartoon. Easing anxiety and giving students the necessary support to learn the material, SPSS: A User-Friendly Approach provides instructors and students with an informative guide to the basics of SPSS.

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• The iClicker Classroom Response System is a versatile polling system developed by educators for educators that makes class time more efficient and interactive. iClicker allows you to ask questions and instantly record students’ responses, gauge students’ understanding and opinions, and take attendance. It can help you gather data on students that you can use to teach statistics, connecting the concepts to students’ lives. iClicker is available at a 10% discount when packaged with Statistics for the Behavioral Sciences, Third Edition.

Instructor Supplements

We understand that one book alone cannot meet the education needs and teaching expectations of the modern classroom. Therefore, we have engaged our colleagues to create a comprehensive supplements package that makes both teaching and learning statistics much easier.

• Instructor’s Resources by Robin Freyberg, Stern College for Women, Yeshiva University, with contributions by Katherine Makarec, William Paterson University. The contents include Teaching Tips and sample course outlines. Each chapter includes a brief overview, discussion questions, classroom activities, handouts, additional reading suggestions, and online resources.
• Test Bank by Jennifer Coleman, Western New Mexico University, with contributions by Kelly M. Goedert, Seton Hall University, and Daniel Cruz, Caldwell College. The Test Bank includes multiple-choice, true/false, fill-in-the-blank, and critical thinking/problem-solving questions for each chapter.
• Diploma Computerized Test Bank (available for Windows or Macintosh on a single CD-ROM). The CD-ROM allows instructors to add an unlimited number of new questions; edit questions; format a test; scramble questions; and include figures, graphs, and pictures. The computerized Test Bank also allows instructors to export into a variety of formats compatible with many Internet-based testing products.
• Worth Publishers supports multiple Course Management Systems with enhanced cartridges that include Test Bank questions and other resources. Cartridges are provided free upon adoption of Statistics for the Behavioral Sciences, Third Edition, and can be requested through Worth’s online catalog at www.worthpublishers.com.

Acknowledgments

We would like to thank the many people who have contributed directly and indirectly to the writing of this text. We want to thank our students at Seton Hall University and William Paterson University for teaching us how to teach statistics in a way that makes sense and for calling our attention to some of the more fun examples you’ll now find in these pages.

Tom: The family members who know me on a daily basis and decide to love me anyway deserve more thanks than words can convey: Donna, Rebekah, Nagesh, Debbie, Anthony, Amy, Elizabeth, Mollie, Jodah, and Benjamin. The close friends, artists, and colleagues who voiced encouragement and timely support also deserve my deep appreciation: Beth, Army, Culley, and Miran Schultz; Laura Cramer-Berness; Ariana DeSimone; J. Allen Suddeth; Nancy Vail; Gerry Esposito; and Sally Ellyson.

My students have always provided a reality check on my teaching methods with the kind of candor that only students engaged in the learning process can bring. And in recent years, our psychology department has made enormous strides by following the rule to “always hire people who are better than you.” Some of those “better than you” colleagues have been a steady source of helpful conversation: Michael Gordon, Amy Learmonth, and Natalie Obrecht. Thank you. And Susan, of course, has been as fine a colleague and friend as I could ever have hoped for.

I also want to thank the people at Worth, all of them. They have a vision for quality textbook publishing that is different from many publishers. I know I speak for Susan as well when I say how deeply we appreciate their level of close cooperation, timely support, and determination to get every detail right. People with those values are what have made Worth’s textbooks so special.

Susan: I am grateful to my Northwestern University professors and classmates for convincing me that statistics can truly be fun. I am also eternally thankful to Beatrix Mellauner for bringing Tom Heinzen and me together as coauthors; it has been a privilege and a pleasure to collaborate with Tom for so many years.

I owe thanks, as well, to my Seton Hall colleagues—Kelly Goedert and Marianne Lloyd in particular—who are the sources for an endless stream of engaging examples. Thanks, too, to Marjorie Levinstein, Katherine Moen, and Ally Reeves, graduate and research assistants extraordinaire, who chased down articles, double-checked arithmetic, and generally helped me carve out time to work on this book. Finally, Seton Hall Department of Psychology secretary, Willie Yaylaci, has contributed in so many ways through her help, support, and friendship; thank you.

Much of the writing of this book took place during my sabbatical and ensuing summers in Bosnia and Herzegovina; I thank my Bosnian friends for their warmth and hospitality every time I visit. A special thank you to the members of the Bojanic and Nolan clans—especially my parents, Diane and Jim, who have patiently endured the barrage of statistics I often inject into everyday conversation. Finally, I am most grateful to my husband, Ivan Bojanic, for the memorable adventures we’ve had (and the statistical observations that have grown out of many of them); Ivan has experienced the evolution of this book through countless road-trip conversations and late-night editorial sessions.

The contributions of the supplements authors are innumerable, and we would like to take a moment to highlight the impressive cast of instructors who have joined our team. Katherine Makarec, Robert Weathersby, and Robin Freyberg are all professionals with a deep interest in creating successful classrooms, and we appreciate the opportunity to work with people of such commitment.

Throughout the writing of the three editions of this textbook, we relied on the criticism, corrections, encouragement, and thoughtful contributions from reviewers, focus group attendees, survey respondents, and class-testers. We thank them for their expertise and for the time they set aside to help us develop this textbook. We also are grateful to the professors who have used our book and then provided specific and valuable feedback; in particular, we thank Harvey H. C. Marmurek and Patricia A. Smiley. Special thanks go to Jennifer Coleman and Byron Reischl at Western New Mexico University and to Kelly Goedert at Seton Hall University for their tireless work in developing the pedagogy with us, providing a responsible accuracy check, and contributing numerous ideas for us to consider as we continue to make this book even better. Special thanks also go to Melanie Maggard at the University of the Rockies and Sherry L. Serdikoff at James Madison University for their invaluable efforts checking the text and exercises.

Tsippa Ackerman

John Jay College

Kenneth Bonanno

Merrimack College

Danuta Bukatko

College of the Holy Cross

Heidi Burross

Pima Community College

Jennifer Coleman

Western New Mexico University

Melanie Conti

College of Saint Elizabeth

Betty Dorr

Fort Lewis College

Nancy Dorr

The College of St. Rose

Kevin Eames

Covenant College

Nancy Gee

State University of New York, Fredonia

Marilyn Gibbons

Texas State University

Elizabeth Haines

William Paterson University

Roberto Heredia

Texas A&M University

Cynthia Ingle

Bluegrass Community and Technical College

E. Jean Johnson

Governors State University

Lauriann Jones-Moore

University of South Florida

Min Ju

State University of New York, New Paltz

Karl Kelley

North Central College

Shelley Kilpatrick

Southwest Baptist University

Megan Knowles

University of Georgia

Paul Koch

Saint Ambrose University

Marika Lamoreaux

Georgia State University

Jennifer Lancaster

St. Francis College

Christine MacDonald

Indiana State University

Suzanne Mannes

Widener University

Walter Marcantoni

Bishop’s University

Kelly Marin

Manhattan College

Connie Meinholdt

Ferris State University

William Merriman

Kent State University

Chris Molnar

LaSalle University

Matthew Mulvaney

State University of New York, Brockport

Angela K. Murray

University of Kansas

Aminda O’Hare

University of Kansas

Sue Oliver

Glendale Community College of Arizona

Stephen O’Rourke

The College of New Rochelle

Debra Oswald

Marquette University

Alison Papdakis

Loyola College in Maryland

Laura Rabin

City University of New York, Brooklyn

Michelle Samuel

Mount St. Mary’s College, Chalon

Ken Savitsky

Williams College

Heidi Shaw

Yakima Valley Community College

Ross B. Steinman

Widener University

Colleen Sullivan

Worcester University

Brian Stults

Florida State University

Melanie Tabak

William Penn University

Mark Tengler

University of Houston, Clear Lake

Patricia Tomich

Kent State University

David Wallace

Fayetteville State University

Elizabeth Weiss

The Ohio State University

Charles Woods

Austin Peay State University

Tiffany Yip

Fordham University

Accuracy Reviewers

Verne Bacharach

Appalachian State University

Jeffrey Berman

University of Memphis

Dennis Goff

Randolph College

Linda Henkel

Fairfield University

Melanie Maggard

University of the Rockies

Kathy Oleson

Reed College

Christy Porter

College of William and Mary

Sherry L. Serdikoff

James Madison University

Alexander Wilson

University of New Brunswick

It has truly been a pleasure for us to work with everyone at Worth Publishers. From the moment we signed there, we have been impressed with the passionate commitment of everyone we encountered at Worth at every stage of the publishing process. Senior vice president Catherine Woods and publisher Kevin Feyen foster that commitment to quality in the Worth culture.

Our original development editor, Michael Kimball, provided an attention to detail that helped us to achieve our vision for this book. Our current development editor, Elaine Epstein, along with director of development for print and digital Tracey Kuehn, have been enormously important in shaping this edition; we rely heavily on their expert guidance and eternally good-humored encouragement. We’re grateful to publisher Ruth Baruth for her astute input regarding creative pedagogy in statistics textbooks. Publisher Charles Linsmeier’s impressive ability to assess ideas and face problems from multiple angles contributed to our successful first edition. We are grateful to senior acquisitions editor Daniel DeBonis for his skill and patience in guiding the revision process for the second and third editions.

Project editor Rob Errera, associate managing editor Lisa Kinne, and production manager Sarah Segal managed the production of the text and worked tirelessly to bring the book to fruition. (We are also grateful to Rob for his patient guidance in keeping us on track and on time during production.) Art director Babs Reingold’s commitment to artistic values in textbook publishing is continually inspiring. Kevin Kall, designer, united beauty with clarity and content in the interior design. Copyeditor Anna Paganelli and her hawk’s eye made our prose more consistent, more accurate, and easier to read. Photo editors Sheena Goldstein and Eileen Liang helped us to select photos that told the stories of statistics. Thanks to each of you for fulfilling Worth’s promise to create a book whose aesthetics so beautifully support the specific pedagogical demands of teaching statistics.

Assistant editor Nadina Persaud, media editor Lauren Samuelson, and associate media editor Anthony Casciano guided the development and creation of the supplements package, making life so much better for so many students and instructors. Marketing manager Lindsay Johnson and associate director of market development Carlise Stembridge quickly understood why we believe so deeply in this book, and each contributed unstinting effort to advocate for this third edition with our colleagues across the country. (And we credit Lindsay for finding several of the new examples in this book!)

We also want to thank the tremendously dedicated Worth team that consistently champions our book while garnering invaluable accolades and critiques from their professor contacts—information that directly leads to a better book. There are far too many of you to thank individually, but we want to send a special shout out to our friend Tom Kling. Generations of Worth authors have benefitted from his enthusiasm, candor, and support. Fortunately, we have been among them.