Intro Stats Technology Update

857 Pages·2011·58.143 MB·English

by  Richard D. De Veaux, Paul F. Velleman, David E. Bock

Z03_WOOD5485_03_SE_ANS1.qxd 10/1/10 3:48 PM Page 1
A01_VELL9121_03_SE_FM PP2.qxd 10/28/10 3:55 PM Page ii
About This Technology Update
Major improvements in technology have been implemented since the rst print-
ing of Intro Stats, Third Edition. Although this Technology Update includes the
same examples, exercises, and statistical content as the original Third Edition, it
also includes updates to re ect the following changes in technology:
On The Computer: This end-of-chapter feature has been updated to include
added coverage of technology help for StatCrunch and R. Instructions for Excel
2003 and the TI-89 graphing calculator are now on the accompanying DVD-ROM.
Videos on DVD: Chapter Review videos on DVD are now included with all new
copies of this book. The videos feature technologies found in the book and the
worked-out Chapter Review exercises. This is an excellent resource for students
who have missed class or wish to review a topic. It is also an excellent resource for
instructors involved with distance learning, individual study, or self-paced learn-
ing programs.
MyStatLab:The MyStatLab course for this text has been updated with the following:
Reading Assessment Questions: These questions help students assess their
understanding of the reading and are effective when used as a prerequisite
for homework assignments.
Additional Exercises:The quantity of exercises has been increased.
Copy/Paste: You can now copy and paste algorithmically regenerated data
sets from exercises in MyStatLab to your clipboard or directly into
StatCrunch for immediate analysis.
A01_VELL9121_03_SE_FM PP2.qxd 10/28/10 3:55 PM Page iii
EDITION
3
Intro Stats
Richard D. De Veaux
Williams College
Paul F. Velleman
Cornell University
David E. Bock
Addison-Wesley
A01_VELL9121_03_SE_FM PP2.qxd 10/28/10 3:55 PM Page iv
Editor in Chief Deirdre Lynch
Acquisitions Editor Christopher Cummings
Senior Content Editor Chere Bemelmans
Senior Managing Editor Karen Wernholm
Senior Production Project Manager Tracy Patruno
Design Manager Andrea Nix
Cover Designer Barbara T. Atkinson
Digital Assets Manager Marianne Groth
Associate Media Producer Vicki Dreyfus
Software Development Bob Carroll and Marty Wright
Senior Marketing Manager Alex Gay
Marketing Assistant Kathleen DeChavez
Senior Author Support/ Joe Vetere
Technology Specialist
Rights and Permissions Advisor Michael Joyce
Senior Manufacturing Buyer Carol Melville
Senior Media Buyer Ginny Michaud
Text Design The Davis Group, Inc.
Production Coordination, PreMediaGlobal
Illustrations, and Composition
Cover photo Pete McArthur
Many of the designations used by manufacturers and sellers to distinguish their
products are claimed as trademarks. Where those designations appear in this book,
and Pearson was aware of a trademark claim, the designations have been printed in
initial caps or all caps.
Library of Congress Cataloging-in-Publication Data
De Veaux, Richard D.
Intro stats technology update / Richard De Veaux, Paul Velleman,
David Bock. 3rd ed.
p. cm.
Rev. ed. of: Intro stats. 3rd ed. c2009.
ISBN 978-0-321-69912-1
1. Statistics Textbooks. I. Velleman, Paul F., 1949- II. Bock, David E.
III. De Veaux, Richard D. Intro stats. IV. Title.
QA276.12.D4 2012
519.5 dc22
2010003342
Copyright © 2012, 2009, 2006 Pearson Education, Inc. All rights reserved. No part of
this publication may be reproduced, stored in a retrieval system, or transmitted, in any
form or by any means, electronic, mechanical, photocopying, recording, or otherwise,
without the prior written permission of the publisher. Printed in the United States of
America. For information on obtaining permission for use of material in this work,
please submit a written request to Pearson Education, Inc., Rights and Contracts
Department, 501 Boylston Street, Suite 900, Boston, MA02116, fax your request to
617-671-3447, or e-mail at http://www.pearsoned.com/legal/permissions.htm.
1 2 3 4 5 6 7 8 9 10 QWD 14 13 12 11 10
ISBN 10: 0-321-69912-2
ISBN 13: 978-0-321-69912-1
A01_VELL9121_03_SE_FM PP2.qxd 10/28/10 3:55 PM Page v
To Sylvia, who has helped me in more ways than she ll ever know,
and to Nicholas, Scyrine, Frederick, and Alexandra,
who make me so proud in everything that they are and do
Dick
To my sons, David and Zev, from whom I ve learned so much,
and to my wife, Sue, for taking a chance on me
Paul
To Greg and Becca, great fun as kids and great friends as adults,
and especially to my wife and best friend, Joanna, for her
understanding, encouragement, and love
Dave
A01_VELL9121_03_SE_FM PP2.qxd 10/29/10 12:39 PM Page vi
Meet the Authors
Richard D. De Veauxis an internationally known educator and consultant. He has taught at the
Wharton School and the Princeton University School of Engineering, where he won a Lifetime Award for
Dedication and Excellence in Teaching. Since 1994, he has been Professor of Statistics at Williams College.
Dick has won both the Wilcoxon and Shewell awards from the American Society for Quality. He is a fellow
of the American Statistical Association. Dick is also well known in industry, where for the past 20 years he has
consulted for such companies as Hewlett-Packard, Alcoa, DuPont, Pillsbury, General Electric, and Chemical
Bank. He has also sometimes been called the Of cial Statistician for the Grateful Dead. His real-world expe-
riences and anecdotes illustrate many of this books chapters.
Dick holds degrees from Princeton University in Civil Engineering (B.S.E.) and Mathematics (A.B.)
and from Stanford University in Dance Education (M.A.) and Statistics (Ph.D.), where he studied with Persi
Diaconis. His research focuses on the analysis of large data sets and data mining in science and industry.
In his spare time he is an avid cyclist and swimmer. He also is the founder and bass for the Diminished
Faculty, an a cappella Doo-Wop quartet at Williams College. Dick is the father of four children.
Paul F. Velleman has an international reputation for innovative Statistics education. He is the
author and designer of the multimedia statistics CD-ROM ActivStats, for which he was awarded the
EDUCOM Medal for innovative uses of computers in teaching statistics, and the ICTCM Award for
Innovation in Using Technology in College Mathematics. He also developed the award-winning statistics
program, Data Desk, and the Internet site Data And Story Library (DASL) (http://dasl.datadesk.com), which
provides data sets for teaching Statistics. Pauls understanding of using and teaching with technology
informs much of this books approach.
Paul has taught Statistics at Cornell University since 1975. He holds an A.B. from Dartmouth College in
Mathematics and Social Science, and M.S. and Ph.D. degrees in Statistics from Princeton University, where he
studied with John Tukey. His research often deals with statistical graphics and data analysis methods. Paul
co-authored (with David Hoaglin) ABCs of Exploratory Data Analysis. Paul is a Fellow of the American
Statistical Association and of the American Association for the Advancement of Science.
Out of class, Paul sings baritone in a barbershop quartet. He is the father of two boys.
David E. Bock taught mathematics at Ithaca High School for 35 years. He has taught Statistics at Ithaca
High School, Tompkins-Cortland Community College, Ithaca College, and Cornell University. Dave has won
numerous teaching awards, including the MAAs Edyth May Sliffe Award for Distinguished High School
Mathematics Teaching (twice), Cornell Universitys Outstanding Educator Award (three times), and has been
a nalist for New York State Teacher of the Year.
Dave holds degrees from the University at Albany in Mathematics (B.A.) and Statistics/Education (M.S.).
Dave has been a reader and table leader for the APStatistics exam, serves as a Statistics consultant to the
College Board, and leads workshops and institutes for APStatistics teachers. He has recently served as K 12
Education and Outreach Coordinator and a senior lecturer for the Mathematics Department at Cornell
University. His understanding of how students learn informs much of this books approach.
Dave relaxes by biking and hiking. He and his wife have enjoyed many days camping across Canada
and through the Rockies. They have a son, a daughter, and three grandchildren.
vi
A01_VELL9121_03_SE_FM PP2.qxd 10/28/10 3:55 PM Page vii
Contents
Preface ix
Index of Applications xx
PART Exploring and Understanding Data 1
I
CHAPTER 1 Stats Starts Here 2
CHAPTER 2 Data 7
CHAPTER 3 Displaying and Describing Categorical Data 20
CHAPTER 4 Displaying and Summarizing Quantitative Data 48
CHAPTER 5 Understanding and Comparing Distributions 88
CHAPTER 6 The Standard Deviation as a Ruler and the Normal Model 121
Review of Part I
Exploring and Understanding Data 154
Exploring Relationships Between Variables 165
PART
II
CHAPTER 7 Scatterplots, Association, and Correlation 166
CHAPTER 8 Linear Regression 194
CHAPTER 9 Regression Wisdom 227
*CHAPTER 10 Re-expressing Data: Get It Straight! 252
Review of Part II
Exploring Relationships Between Variables 277
Gathering Data 287
PART
III
CHAPTER 11 Understanding Randomness 289
CHAPTER 12 Sample Surveys 303
CHAPTER 13 Experiments and Observational Studies 329
Review of Part III
Gathering Data 356
Randomness and Probability 363
PART
IV CHAPTER 14 From Randomness to Probability 364
CHAPTER 15 Probability Rules! 384
*Indicates an optional chapter.
vii
A01_VELL9121_03_SE_FM PP2.qxd 10/28/10 3:55 PM Page viii
viii CONTENTS
*CHAPTER 16 Random Variables 409
*CHAPTER 17 Probability Models 432
Review of Part IV
Randomness and Probability 451
PART
From the Data at Hand to the World at Large 457
V
CHAPTER 18 Sampling Distribution Models 458
CHAPTER 19 Con dence Intervals for Proportions 486
CHAPTER 20 Testing Hypotheses About Proportions 508
CHAPTER 21 More About Tests 531
CHAPTER 22 Comparing Two Proportions 557
Review of Part V
From the Data at Hand to the World at Large 579
PART
Learning About the World 585
VI
CHAPTER 23 Inferences About Means 586
CHAPTER 24 Comparing Means 616
CHAPTER 25 Paired Samples and Blocks 650
Review of Part VI
Learning About the World 675
PART
Inference When Variables Are Related 685
VII
CHAPTER 26 Comparing Counts 686
CHAPTER 27 Inferences for Regression 720
Review of Part VII
Inference When Variables Are Related 758
*CHAPTER 28 Analysis of Variance on the DVD
*CHAPTER 29 Multiple Regression on the DVD
Appendixes A-1
A Answers A-2
B Photo Acknowledgments A-41
C Index A-42
D Tables and Selected Formulas A-57
*Indicates an optional chapter.
A01_VELL9121_03_SE_FM PP2.qxd 10/28/10 3:55 PM Page ix
Preface
About the Book
Weve been thrilled with the feedback weve received from instructors
and students using Intro Stats. If there is a single hallmark of this
book it is that students actually read it. We have reports from every
level from high school to graduate school that students nd our
books easy and even enjoyable to read. We strive for a conversational, approach-
able style, and introduce anecdotes to maintain students interest. And it works.
Instructors report their amazement that students are voluntarily reading ahead
of their assignments. Students write to tell us (to their amazement) that they
actuallyenjoyed the book.
Unlike any other introductory book in the market, Intro Statsis written from the
ground up with the understanding that Statistics is practiced with technology.
This insight informs everything from our choice of forms for equations (favoring
intuitive forms over calculation forms) to our extensive use of real data. Most
important, it allows us to focus on teaching Statistical Thinking rather than calcu-
lation. The questions that motivate each of our hundreds of examples are not
how do you nd the answer? but how do you think about the answer?
Our Goal: Read This Book!
The best text in the world is of little value if students dont read it. Here are some
of the ways we have made IntroStats,Third Edition even more approachable:
Readability. Youll see immediately that this book doesnt read like other
Statistics texts. The style is both colloquial and informative, engaging stu-
dents to actually read the book to see what it says.
Humor. We know that humor is the best way to promote learning. You will
nd quips and wry comments throughout the narrative, in margin notes, and
in footnotes. If we sometimes cross the line and seem to trivialize something
important, we apologize.
Informality. Our informal diction doesnt mean that the subject matter is cov-
ered lightly or informally. We have tried to be precise and, wherever possible,
to offer deeper explanations and justi cations than those found in most intro-
ductory texts.
Focused lessons. The chapters are shorter than in most other texts, to make it
easier to focus on one topic at a time.
Consistency. Weve worked hard to avoid the do what we say, not what
we do trap. Having taught the importance of plotting data and checking
assumptions and conditions, we have been careful to model that behavior
right through the rest of the book. (Check the exercises in Chapter 27 and
youll see us still requiring and demonstrating the plots and checks that were
introduced in the early chapters.) This consistency helps to reinforce these
fundamental principles.
ix
A01_VELL9121_03_SE_FM PP2.qxd 10/28/10 3:56 PM Page x
x PREFACE
The need to read. Students who plan just to skim the book may nd our pre-
sentation a bit frustrating. The important concepts, de nitions, and sample
solutions dont sit in little boxes. This is a book that needs to be read, so weve
tried to make the reading experience enjoyable.
New to the Third Edition
The third edition of Intro Stats continues and extends the successful innovations
pioneered in our books, teaching Statistics and statistical thinking as it is prac-
ticed today. We ve rewritten sections throughout the book to make them clearer
and more interesting. Weve introduced new up-to-the-minute motivating exam-
ples throughout. Many chapters lead with new examples and we follow through
with analyses of the data from those examples. And, weve added a number of
new features, each with the goal of making it even easier for students to put the
concepts of Statistics together into a coherent whole.
u
Where Are We Going? Each chapter now starts with an introduction that points
Where are we going? out the kinds of questions students will learn how to answer in the chapter.
Each chapter ends with a What Have We Learned? summary to help students
review what they should understand from the chapter.
u
For Example. In every chapter, youll now nd new worked examples that illus-
FOR EXAMPLE trate how to apply the concepts and methods discussed up to that point. Weve
added approximately 4 of these examples, called For Example, to each chapter for
further illustration. (With 27 chapters, thats more than 100 new illustrative
examples.) As we introduce each important, new concept, we provide a focused
example applying it usually with real up-to-the-minute data. But these arent
isolated examples. We carry the discussion through the chapter with each
For Example, picking up the story and moving it forward as students learn more
about the topic of the chapter. Providing these examples in sequences enhances
and illustrates the story of each chapter.
u
STEP BY STEP EXAMPLE Step-by-Step Worked Examples. Weve brought our innovative Think/Show/Tell
Step-by-Step examples up-to-date with new examples and data, and restruc-
tured them so that each example begins with a clear question to address and
ends with a conclusion that answers that question.
u
JUST CHECKING Just Checking. This edition contains even more Just Checking exercises within
chapters to help students ensure they understand the key ideas.
u
ActivStats Pointers. Each chapter includes pointers to ActivStats activities (ani-
mations, simulations, activities, videos) that parallel the books discussions to
enhance learning. In the third edition, the ActivStatspointers have been revised
for clarity and now indicate exactly what they are pointing to activity, video,
simulation, etc.
u
Exercises. Weve added hundreds of new exercises, including more single-
concept exercises at the beginning of each set so students can be sure they have
a clear understanding of each important topic before theyre asked to tie them
all together in more comprehensive exercises. Exercises have been updated
with the most recent data. Many come from news stories; some from recent
research articles. Whenever possible, the data are on the DVD so students can
explore them further.
u
Data Sources. Most of the data used in examples and exercises are from real-world
sources, and weve listed more sources in this edition. Whenever we could, weve