ABOUT THE AUTHOR

Mario F. Triola is a Professor Emeritus of Mathematics at Dutchess Community College, where he has taught statistics for over 30 years. Marty is the author of Essentials of Statistics, Elementary Statistics Using Excel, Mathematics in the Modern World, and Survey of Mathematics. He is a co-author of Statistical Reasoning for Everyday Life, Business Statistics, and Introduction to Technical Mathematics. He designed the original STATDISK statistical software package, and technology that support statistics education. Outside the classroom, Marty's consulting work includes the mathematical design of casino slot machines and fishing rods, and he has worked with attorneys in determining probabilities in paternity lawsuits, identifying salary inequities based on gender, and analyzing disputed election results. Marty has testified as an expert witness in New York State Supreme Court for an election dispute involving a former student. Marty was a recent writing team member of the Project Coalition with NASA and the American Mathematics Association of Two-Year Colleges.

When he's not working, Marty enjoys travel, golf, tennis, running, hiking, and anything that flies. He has a commercial pilot's license with an instrument rating, and has flown airplanes, helicopters, sail planes, hang gliders, and hot air balloons. His passion for flying has included parachute jumps, flying in a Goodyear blimp, and parasailing.

The Text and Academic Authors Association has awarded Mario F. Triola a "Texty" for Excellence for his work on Elementary Statistics.

PREFACE

Audience/Prerequisites
Elementary Statistics is written for students majoring in any field. Although the use of algebra is minimal, students should have completed at least a high school or college elementary algebra course. In many cases, underlying theory is included, but this book does not stress the mathematical rigor more suitable for mathematics majors. Because the many examples and exercises cover a wide variety of different and interesting statistical applications, Elementary Statistics is appropriate for students pursuing majors in a wide variety of disciplines ranging from the social sciences of psychology and sociology to areas such as education, the allied health fields, business, economics, engineering, the humanities, the physical sciences, journalism, communications, and liberal arts.

Technology
Elementary Statistics, Ninth Edition, can be used easily without reference to any specific technology. Many instructors continue to use editions of this book with students using nothing more than a variety of different scientific calculators. However, for those who choose to supplement the course with specific technology, both in-text and supplemental materials are available. See below for specific information.

Organization Changes

In Chapter 5, Sections 5-3 and 5-4 from the Eighth Edition (nonstandard normal distributions) are now combined in Section 5-3. This change is motivated by the new format of Table A-2, which makes it easier for students to work with normal distributions.
In Chapter 5 there is a new Section 5-4 describing "Sampling Distributions and Estimators."
In Chapters 6, 7, and 8, confidence intervals and hypothesis testing procedures now begin with proportions, which students generally find more interesting than means. Also, the procedures for working with proportions are simpler, allowing students to better focus on the new methods of inferential statistics.
Section 6-4 from the Eighth Edition (Sample Size Required to Estimate μ) is now included in Section 6-3 (Estimating a Population Mean: σ Known) along with confidence intervals for estimating a population mean μ.
Because instructors include the topic of statistical process control less frequently than the topic of nonparametric statistics, those two topics have been switched so that Chapter 12 now covers methods of nonparametric statistics and Chapter 13 covers statistical process control.

Content Changes

Procedures In Chapters 6, 7, 8, there is a change from "n > 30" to "σ known" as a key criterion for choosing between the normal and t distributions. This change reflects the common practice used by working professionals, it provides more accurate results and it is better for students moving on to other statistics courses, yet it is not much more difficult than using the "n > 30" criterion.
Tables There is a new format for the important normal distribution in Table A-2: Cumulative areas from the left are now listed on two pages. Students generally find this format easier to use. Table A-3 has been expanded to include more of the larger sample sizes for the Student t distribution.
Notation In hypothesis testing, the symbols ≥ and ≤ are no longer used in expressions of the null hypothesis. For claims about a specific value of a parameter, only the equal symbol = is used. This change reflects the practice used by the overwhelming majority of professionals who use methods of statistics and report findings in professional journals.
Data Sets Appendix B now includes 30 data sets (instead of 20), including 14 that are new.
Icons Technology icons are now used to identify exercises based on larger data sets from Appendix B, which are best completed by using software or a TI-83 Plus calculator.
Interpreting Results Throughout the book there is even greater emphasis on interpreting results. Instead of simply obtaining answers, the implications and consequences of answers are considered. For example, when discussing probability in Chapter 3, instead of simply finding probability values, we interpret them by differentiating between events that are usual and those that are unusual. With hypothesis testing, we don't simply end with a conclusion of rejecting or failing to reject a null hypothesis, we proceed to state a practical conclusion that addresses the real issue. Students are encouraged to think about the implications of results instead of cranking out cookbook results that make no real sense.

Flexible Syllabus
The organization of this book reflects the preferences of most statistics instructors, but there are two common variations that can be easily used with this Ninth Edition:

Early coverage of correlation/regression: Some instructors prefer to cover the basics of correlation and regression early in the course, such as immediately following the topics of Chapter 2. Sections 9-2 (Correlation) and 9-3 (Regression) can be covered early in the course. Simply omit the subsection in Section 9-2 clearly identified as "Formal Hypothesis Test (Requires Coverage of Chapter 7)."
Minimum probability: Some instructors feel strongly that coverage of probability should be extensive, while others feel just as strongly that coverage should be kept to a bare minimum. Instructors preferring minimum coverage can include Section 3-2 while skipping the remaining sections of Chapter 3, as they are not essential for the chapters that follow. Many instructors prefer to cover only the fundamentals of probability along with the basics of the addition rule and multiplication rule, and the coverage of the multiplication rule (Sections 3-4 and 3-5) now offers that flexibility.

Exercises
There are over 1500 exercises—more than 58% of them new! In response to requests by users of the previous edition, there are now more of the simpler exercises that are based on small data sets. Many more of the exercises require interpretation of results. Because exercises are of such critical importance to any statistics book, great care has been taken to ensure their usefulness, relevance, and accuracy. Three statisticians have read carefully through the final stages of the book to verify accuracy of the text material and exercise answers. Exercises are arranged in order of increasing difficulty by dividing them into two groups: (1) Basic Skills and Concepts and (2) Beyond the Basics. The Beyond the Basics exercises address more difficult concepts or require a somewhat stronger mathematical background. In a few cases, these exercises also introduce a new concept. Real data: 64% of the exercises use real data. Because the use of real data is such an important consideration for students, hundreds of hours have been devoted to finding real, meaningful, and interesting data. In addition to the real data included throughout the book, many exercises refer to the 30 data sets listed in Appendix B.

Hallmark Features
Beyond an interesting and accessible (and sometimes humorous) writing style, great care has been taken to ensure that each chapter of Elementary Statistics will help students understand the concepts presented. The following features are designed to help meet that objective:

Chapter-opening features: A list of chapter sections previews the chapter for the student; a chapter-opening problem, using real data, then motivates the chapter material; and the first section is a chapter overview that provides a statement of the chapter's objectives.
End-of-chapter features:
• A Chapter Review summarizes the key concepts and topics of the chapter;
• Review Exercises offer practice on the chapter concepts and procedures;
• Cumulative Review Exercises reinforce earlier material;
• From Data to Decision: Critical Thinking is a capstone problem that requires critical thinking and a writing component;
• Cooperative Group Activities encourage active learning in groups;
• Technology Projects are for use with STATDISK, Minitab, Excel, or a TI-83 Plus calculator;
• Internet Projects involve students with Internet data sets and, in some cases, applets.
Margin Essays: The text includes 120 margin essays, which illustrate uses and abuses of statistics in real, practical, and interesting applications. Topics include "Do Boys or Girls Run in the Family?, "Accuracy of Vote Counts," "Test of Touch Therapy," and "Picking Lottery Numbers."
Flowcharts: These appear throughout the text to simplify and clarify more complex concepts and procedures.
Statistical Software: STATDISK, Minitab, Excel and TI-83 PLUS instructions and output appear throughout the text.
Real Data Sets: These are used extensively throughout the entire book. Appendix B lists 30 data sets, 14 of which are new. These data sets are provided in printed form in Appendix B, and in electronic form on the Web site and the CD bound in the back of the book. The data sets include such varied topics as ages of Queen Mary stowaways, alcohol and tobacco use in animated children's movies, eruptions of the Old Faithful geyser, diamond prices and characteristics, and more financial and rating data.
Interviews: Every chapter of the text includes author-conducted interviews with professional men and women in a variety of fields who use statistics in their day-to-day work.
Quick-Reference Endpapers: Tables A-2 and A-3 (the normal and t distributions) are reproduced on the front inside cover pages. A symbol table is included at the back of the book for quick and easy reference to key symbols.
Detachable Formula/Table Card: This insert, organized by chapter, gives students a quick reference for studying, or for use when taking tests (if allowed by the instructor).
CD-ROM: prepared by Mario F. Triola and packaged with every new copy of the text, includes the data sets (except for Data Set 4) from Appendix B in the textbook. These data sets are stored as text files, Minitab worksheets, SPSS files, SAS files, Excel workbooks, and a TI-83 Plus application. The CD also includes programs for the TI-83 Plus ® graphing calculator, STATDISK Statistical Software (Version 9.1), and the Excel Add-In, which is designed to enhance the capabilities of Excel's statistics programs.