Elementary statistics looking at the big picture part 1

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Elementary
Statistics


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Elementary
Statistics
LO O K I N G AT T H E B I G P I C T U R E

Nancy pfenning
University of Pittsburgh

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Elementary Statistics:
Looking at the Big Picture
Nancy Pfenning
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Contents

Preface

xv

1 Introduction: Variables and Processes in Statistics

1

Types of Variables: Categorical or Quantitative . . . . . . . . . . . . . . . . . . . . . .

Students Talk Stats: Identifying Types of Variables . . . . . . . . . . . . . . . . . . .
Handling Data for Two Types of Variables . . . . . . . . . . . . . . . . . . . . . . . . .
Roles of Variables: Explanatory or Response . . . . . . . . . . . . . . . . . . . . . . .
Statistics as a Four-Stage Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2
3

5
7
9

Summary 11 / Exercises 11

PA R T I

Data Production

16

2 Sampling: Which Individuals Are Studied

18

Sources of Bias in Sampling: When Selected Individuals Are Not
Representative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Probability Sampling Plans: Relying on Randomness . . . . . . . . . . . . . . . . .
The Role of Sample Size: Bigger Is Better If the Sample Is Representative . .
From Sample to Population: To What Extent Can We Generalize? . . . . . . .
Students Talk Stats: Seeking a Representative Sample . . . . . . . . . . . . . . . . .

18
20
21
22
23

Summary 25 / Exercises 25

3 Design: How Individuals Are Studied

30

3.1

Various Designs for Studying Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Identifying Study Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Observational Studies versus Experiments: Who Controls the Variables? . .
Errors in Studies’ Conclusions: The Imperfect Nature of Statistical Studies .

30
32
33
35

3.2

Sample Surveys: When Individuals Report Their Own Values . . . . . . . . . . .
Sources of Bias in Sample Surveys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

38
38

3.3

Observational Studies: When Nature Takes Its Course . . . . . . . . . . . . . . . .
Confounding Variables and Causation . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Paired or Two-Sample Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Prospective or Retrospective Studies: Forward or Backward in Time . . . . .

46
46
48
49

3.4

Experiments: When Researchers Take Control . . . . . . . . . . . . . . . . . . . . . .
Randomized Controlled Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Double-Blind Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
“Blind” Subjects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
“Blind” Experimenters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pitfalls in Experimentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Modifications to Randomization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

51
52
53
53
54
55
57
vii


viii

Contents

Students Talk Stats: Does Watching TV Cause ADHD? Considering
Study Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

63

Summary 63 / Exercises 65

PA R T I I

Displaying and Summarizing
Data 70

4 Displaying and Summarizing Data for a Single Variable
4.1

72

Single Categorical Variable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Summaries and Pie Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Role of Sample Size: Why Some Proportions Tell Us More Than
Others Do . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bar Graphs: Another Way to Visualize Categorical Data . . . . . . . . . . . . . . .
Mode and Majority: The Value That Dominates . . . . . . . . . . . . . . . . . . . . .
Revisiting Two Types of Bias . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Students Talk Stats: Biased Sample, Biased Assessment . . . . . . . . . . . . . . . .

74
75
77

77
78

4.2

Single Quantitative Variables and the Shape of a Distribution . . . . . . . . . . .
Thinking about Quantitative Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stemplots: A Detailed Picture of Number Values . . . . . . . . . . . . . . . . . . . . .
Histograms: A More General Picture of Number Values . . . . . . . . . . . . . . .

82
83
85
89

4.3

Center and Spread: What’s Typical for Quantitative Values, and How
They Vary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Five-Number Summary: Landmark Values for Center and Spread . . . . . . . .
Boxplots: Depicting the Key Number Values . . . . . . . . . . . . . . . . . . . . . . . .
Mean and Standard Deviation: Center and Spread in a Nutshell . . . . . . . . .

93
93
95
98

4.4

Normal Distributions: The Shape of Things to Come . . . . . . . . . . . . . . . . .
The 68-95-99.7 Rule for Samples: What’s “Normal” for a Data Set . . . . . .
From a Histogram to a Smooth Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Standardizing Values of Normal Variables: Storing Information
in the Letter z . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Students Talk Stats: When the 68-95-99.7 Rule Does Not Apply . . . . . . . .
“Unstandardizing” z-Scores: Back to Original Units . . . . . . . . . . . . . . . . . .
The Normal Table: A Precursor to Software . . . . . . . . . . . . . . . . . . . . . . . .

72
72

108
110
113
114
117
118
119

Summary 125 / Exercises 127

5 Displaying and Summarizing Relationships

133

5.1

Relationships between One Categorical and One Quantitative Variable . . .
Different Approaches for Different Study Designs . . . . . . . . . . . . . . . . . . . .

Displays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Summaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Notation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data from a Two-Sample Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data from a Several-Sample Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data from a Paired Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Students Talk Stats: Displaying and Summarizing Paired Data . . . . . . . . . .
Generalizing from Samples to Populations: The Role of Spreads . . . . . . . . .
The Role of Sample Size: When Differences Have More Impact . . . . . . . . .

133
133
134
134
134
134
137
138
139
141
143

5.2

Relationships between Two Categorical Variables . . . . . . . . . . . . . . . . . . . . 150
Summaries and Displays: Two-Way Tables, Conditional Percentages,
and Bar Graphs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
The Role of Sample Size: Larger Samples Let Us Rule Out Chance . . . . . . . 156

Contents

Comparing Observed and Expected Counts . . . . . . . . . . . . . . . . . . . . . . . . 156
Confounding Variables and Simpson’s Paradox: Is the Relationship
Really There? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
5.3

Relationships between Two Quantitative Variables . . . . . . . . . . . . . . . . . . .
Displays and Summaries: Scatterplots, Form, Direction, and Strength . . . . .
Correlation: One Number for Direction and Strength . . . . . . . . . . . . . . . . .
When the Correlation Is 0, ϩ1, or Ϫ1 . . . . . . . . . . . . . . . . . . . . . . . . . .
Correlation as a Measure of Direction and Strength . . . . . . . . . . . . . . . .
A Closer Look at Correlation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Correlation Is Unaffected by the Roles of Explanatory
and Response Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Correlation Is Unaffected by Units of Measurement . . . . . . . . . . . . . . . .
Least Squares Regression Line: What We See in a Linear Plot . . . . . . . . . . .
A Closer Look at Least Squares Regression . . . . . . . . . . . . . . . . . . . . . . . . .
Residuals: Prediction Errors in a Regression . . . . . . . . . . . . . . . . . . . . . .
Spread s about the Line versus Spread sy about the Mean Response . . . .
The Effect of Explanatory and Response Roles on the Regression Line .
Influential Observations and Outliers . . . . . . . . . . . . . . . . . . . . . . . . . . .
Students Talk Stats: How Outliers and Influential Observations Affect
a Relationship . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sample versus Population: Thinking Beyond the Data at Hand . . . . . . . . . .
The Role of Sample Size: Larger Samples Get Us Closer to the Truth . . . . .
Time Series: When Time Explains a Response . . . . . . . . . . . . . . . . . . . . . . .
Additional Variables: Confounding Variables, Multiple Regression . . . . . . .
Students Talk Stats: Confounding in a Relationship between
Two Quantitative Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

165
166
170
171
173
174
175
176
177
182
182
183
184
185
186
187
188
189
191
191

Summary 204 / Exercises 206

PA R T I I I

Probability

6 Finding Probabilities

224

226

6.1

The Meaning of “Probability” and Basic Rules . . . . . . . . . . . . . . . . . . . . . .
Permissible Probabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Probabilities Summing to One . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Probability of “Not” Happening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Probability of One “Or” the Other for Non-overlapping Events . . . . . . . . .
Probability of One “And” the Other for Two Independent Events . . . . . . .

226
229
229
231
231
233

6.2

More General Probability Rules and Conditional Probability . . . . . . . . . . .
Probability of One “Or” the Other for Any Two Events . . . . . . . . . . . . . . .
Probability of Both One “And” the Other Event Occurring . . . . . . . . . . . .
Students Talk Stats: Probability as a Weighted Average of Conditional
Probabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Conditional Probability in Terms of Ordinary Probabilities . . . . . . . . . . . .
Checking for Independence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Counts Expected If Two Variables Are Independent . . . . . . . . . . . . . . . . . .

238
239
241
245
246
247
250

Summary 256 / Exercises 257

7 Random Variables
7.1

267

Discrete Random Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Probability Distributions of Discrete Random Variables . . . . . . . . . . . . . . .
The Mean of a Random Variable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Standard Deviation of a Random Variable . . . . . . . . . . . . . . . . . . . . . .
Rules for the Mean and Standard Deviation of a Random Variable . . . . . .

268
269
276
278
280

ix

x

Contents

7.2

7.3

Binomial Random Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
What Makes a Random Variable “Binomial”? . . . . . . . . . . . . . . . . . . . . . .
The Mean and Standard Deviation of Sample Proportions . . . . . . . . . . . . .
Students Talk Stats: Calculating and Interpreting the Mean and Standard
Deviation of Count or Proportion . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Shape of the Distribution of Counts or Proportions: The Central
Limit Theorem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Continuous Random Variables and the Normal Distribution . . . . . . . . . . .
Discrete versus Continuous Distributions . . . . . . . . . . . . . . . . . . . . . . . . . .
When a Random Variable Is Normal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The 68-95-99.7 Rule for Normal Random Variables . . . . . . . . . . . . . . . . . .
Standardizing and Unstandardizing: From Original Values to z
or Vice Versa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Estimating z Probabilities with a Sketch of the 68-95-99.7 Rule . . . . . . . . .
Nonstandard Normal Probabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tails of the Normal Curve: The 90-95-98-99 Rule . . . . . . . . . . . . . . . . . . .
Students Talk Stats: Means, Standard Deviations, and Below-Average
Heights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

291
291

295
297
299
311
312
315
316
319
319
323
326
329

Summary 335 / Exercises 337

8 Sampling Distributions

344

Categorical Variables: The Behavior of Sample Proportions . . . . . . . . . . . . 344
Quantitative Variables: The Behavior of Sample Means . . . . . . . . . . . . . . . 345
8.1

The Behavior of Sample Proportion in Repeated Random Samples . . . . . . . 346
Thinking about Proportions from Samples or Populations . . . . . . . . . . . . . 346
Center, Spread, and Shape of the Distribution of Sample Proportion . . . . . . 348

8.2

The Behavior of Sample Mean in Repeated Random Samples . . . . . . . . . . .

Thinking about Means from Samples or Populations . . . . . . . . . . . . . . . . .
The Mean of the Distribution of Sample Mean . . . . . . . . . . . . . . . . . . . . . .
The Standard Deviation of the Distribution of Sample Mean . . . . . . . . . . .
The Shape of the Distribution of Sample Mean: The Central
Limit Theorem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Center, Spread, and Shape of the Distribution of Sample Mean . . . . . . . . . .
Normal Probabilities for Sample Means . . . . . . . . . . . . . . . . . . . . . . . . . . .
Students Talk Stats: When Normal Approximations Are Appropriate . . . . .

356
356
358
358
360
360
362
365

Summary 371 / Exercises 372

PA R T I V

Statistical Inference

9 Inference for a Single Categorical Variable
9.1

9.2

386

388

Point Estimate and Confidence Interval: A Best Guess and a Range
of Plausible Values for Population Proportion . . . . . . . . . . . . . . . . . . . . . . .
Probability versus Confidence: Talking about Random Variables
or Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
95% Confidence Intervals: Building around Our Point Estimate . . . . . . . . .
The Role of Sample Size: Closing In on the Truth . . . . . . . . . . . . . . . . . . . .
Confidence at Other Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Deciding If a Particular Value Is Plausible: An Informal Approach . . . . . . .
The Meaning of a Confidence Interval: What Exactly Have We Found? . . .
Students Talk Stats: Interpreting a Confidence Interval . . . . . . . . . . . . . . . .

390
392
394
398
400
403
404
405

Hypothesis Test: Is a Proposed Population Proportion Plausible? . . . . . . . . 413
Three Forms of Alternative Hypothesis: Different Ways to Disagree . . . . . . 416
One-Sided or Two-Sided Alternative Hypothesis . . . . . . . . . . . . . . . . . . . . . 425


Contents

How Small Is a “Small” P-Value? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

The Role of Sample Size in Conclusions for Hypothesis Tests . . . . . . . . . . .
When to Reject the Null Hypothesis: Three Contributing Factors . . . . . . . .
Students Talk Stats: Interpreting a P-Value . . . . . . . . . . . . . . . . . . . . . . . . .
Type I or II Error: What Kind of Mistakes Can We Make? . . . . . . . . . . . . .
Students Talk Stats: What Type of Error Was Made? . . . . . . . . . . . . . . . . .
Relating Results of Test with Confidence Interval: Two Sides of the
Same Coin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Language of Hypothesis Tests: What Exactly Do We Conclude? . . . . .
Students Talk Stats: The Correct Interpretation of a Small P-Value . . . . . . .
Students Talk Stats: The Correct Interpretation When a P-Value Is Not
Small . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The “Critical Value” Approach: Focusing on the Standard Score . . . . . . . .

429
430
431
432
433
435
435
436
437
437
438

Summary 451 / Exercises 454

10 Inference for a Single Quantitative Variable

461

10.1 Inference for a Mean When Population Standard Deviation Is Known
or Sample Size Is Large . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A Confidence Interval for the Population Mean Based on z . . . . . . . . . . . .
95% Confidence Intervals with z . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Students Talk Stats: Confidence Interval for a Mean: Width, Margin
of Error, Standard Deviation, and Standard Error . . . . . . . . . . . . . . . . .
Role of Sample Size: Larger Samples, Narrower Intervals . . . . . . . . . . . .
Intervals at Other Levels of Confidence with z . . . . . . . . . . . . . . . . . . . .
Interpreting a Confidence Interval for the Mean . . . . . . . . . . . . . . . . . . .
Students Talk Stats: Correctly Interpreting a Confidence Interval
for the Mean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A z Hypothesis Test about the Population Mean . . . . . . . . . . . . . . . . . . . . .

462
464
465
469
471
472
473
473
474

10.2 Inference for a Mean When the Population Standard Deviation Is Unknown
and the Sample Size Is Small . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A t Confidence Interval for the Population Mean . . . . . . . . . . . . . . . . . . . .
95% Confidence Intervals with t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Intervals at Other Levels of Confidence with t . . . . . . . . . . . . . . . . . . . .
A t Hypothesis Test about the Population Mean . . . . . . . . . . . . . . . . . . . . .

Students Talk Stats: Practical Application of a t Test . . . . . . . . . . . . . . . . . .

480
482
482
484
486
488

10.3 A Closer Look at Inference for Means . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A One-Sided or Two-Sided Alternative Hypothesis about a Mean . . . . . . . .
The Role of Sample Size and Spread: What Leads to Small P-Values? . . . . .
Type I and II Errors: Mistakes in Conclusions about Means . . . . . . . . . . . .
Relating Tests and Confidence Intervals for Means . . . . . . . . . . . . . . . . . . .
Correct Language in Hypothesis Test Conclusions about a Mean . . . . . . . .
Robustness of Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

491
491
493
494
495
496
498

Summary 503 / Exercises 505

11 Inference for Relationships between Categorical and Quantitative
Variables 520
11.1 Inference for a Paired Design with t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 522

Hypothesis Test in a Paired Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 522
Confidence Interval in a Paired Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . 524
11.2 Inference for a Two-Sample Design with t . . . . . . . . . . . . . . . . . . . . . . . . . .
The Two-Sample t Distribution and Test Statistic . . . . . . . . . . . . . . . . . . . .
Hypothesis Test in a Two-Sample Design . . . . . . . . . . . . . . . . . . . . . . . . . .
Confidence Interval in a Two-Sample Design . . . . . . . . . . . . . . . . . . . . . . .
The Pooled Two-Sample t Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Students Talk Stats: Ordinary versus Pooled Two-Sample t . . . . . . . . . . . . .

528
528
530
534
536
537

xi


xii

Contents

11.3 Inference for a Several-Sample Design with F: Analysis of Variance . . . . . . .
The F Statistic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The F Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Solving Several-Sample Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The ANOVA Table: Organizing What We Know about F . . . . . . . . . . . . .
The ANOVA Alternative Hypothesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Assumptions of ANOVA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

543
545
550
552
555
557
558

Summary 566

Students Talk Stats: Reviewing Relationships between Categorical
Explanatory and Quantitative Response Variables . . . . . . . . . . . . . . . . . 566
Exercises 571

12 Inference for Relationships between Two Categorical Variables

591

12.1 Comparing Proportions with a z Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

592

12.2 Comparing Counts with a Chi-Square Test . . . . . . . . . . . . . . . . . . . . . . . . .
Relating Chi-Square to z . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Table of Expected Counts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Comparing Observed to Expected Counts . . . . . . . . . . . . . . . . . . . . . . . . . .
The Chi-Square Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Chi-Square Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sample Size and Chi-Square Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . .

598
598
599
600
602
604
604

Summary 613 / Exercises 614

13 Inference for Relationships between Two Quantitative Variables

628

13.1 Inference for Regression: Focus on the Slope of the Regression Line . . . . . .
Setting the Stage: Summarizing a Relationship for Sampled Points . . . . . . .
Distinguishing between Sample and Population Relationships . . . . . . . . . .
A Model for the Relationship between Two Quantitative Variables
in a Population . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Distribution of Sample Slope b1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Distribution of Standardized Sample Slope t . . . . . . . . . . . . . . . . . . . . .
Hypothesis Test about the Population Slope with t: A Clue
about the Relationship . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Students Talk Stats: No Evidence of a Relationship . . . . . . . . . . . . . . . . . . .
Confidence Interval for the Slope of the Population Regression Line . . . . . .

629
630
631

634
636
637
638
643
644

13.2 Interval Estimates for an Individual or Mean Response . . . . . . . . . . . . . . . . 651
Summary 662 / Exercises 664

14 How Statistics Problems Fit into the Big Picture

677

14.1 The Big Picture in Problem Solving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 677
Students Talk Stats: Choosing the Appropriate Statistical Tools: Question 1 678
Students Talk Stats: Choosing the Appropriate Statistical Tools: Question 2 679
Students Talk Stats: Choosing the Appropriate Statistical Tools: Question 3 680
Exercises 683

15 Non-parametric Methods

(available online)

15.1 The Sign Test as an Alternative to the Paired t Test
15.2 The Rank-Sum Test as an Alternative to the Two-Sample t Test
Wilcoxon rank-sum test
15.3 Summary of Non-parametrics
Exercises

Contents

16 Two-Way ANOVA

(available online)

Exercises

17 Multiple Regression

(available online)

Exercises

Solutions to Selected Exercises
Endnotes
Index

987

1007

689

xiii


Endnotes
Chapter 1

1. Kenneth R. Weiss, “New Test-Taking Skill: Working the System,” Los Angeles
Times, January 9, 2000.
2. “Racial Gaps in Education Cause Income Tiers,” The Michigan Daily,
March 21, 2003.
3. Bootle Cosgrove-Mather, “Are Feeding Tubes Over-Prescribed?” CBS News,
July 2, 2003.
4. Trevor Butterworth, “The Duh Report: Smarties Stay Sober, Narcissists Crave
Fame, Cell Phones Addictive,” STATS, September 15, 2006.
5. “Stronger Sunscreens May Increase Exposure, Cancer Risk,” Augusta
Chronicle, August 4, 1999.
6. “Teens Most Likely to Have Sex at Home,” USA Today, September 26, 2002.
7. “Living Longer,” The New York Times, September 16, 2007.
8. “Where You Live Can Affect How Long You Live,” NPR Morning Edition,
September 11, 2006.
9. “Smoke Out/Teens Get the Message on the Hazards of Tobacco,” Editorial,
Pittsburgh Post-Gazette, July 8, 2004.

Chapter 2
1. Marylynn Uricchio, “Larry Flint,” Pittsburgh Post-Gazette, October 15, 2001.
2. Scripps Survey Research Center at Ohio University, newspoll.org
(accessed October 28, 2002).
3. "1 in 4 Credit Reports Has Serious Errors, Group Says," USA Today,
June 17, 2004.
4. Scripps Survey Research Center at Ohio University, newspoll.org
(accessed August 15, 2003).
5. Pricing Strategy Associates, (accessed
May 3, 2009). Copyright 2004–2007, Marlene Jensen.
6. Scripps Survey Research Center at Ohio University, newspoll.org
(accessed May 18, 2003).
7. Linda Wilson Fuoco, “Dogs That Fail the ‘Pinch Test,’” Pittsburgh PostGazette, December 8, 2004.

8. “Couch Potato Nation,” Pittsburgh Post-Gazette, January 12, 1999.
9. “Written Word Helps Wounds Heal,” BBC News, September 6, 2003.
10. Bob Herbert, “Countdown to Execution No. 300,” The New York Times,
March 10, 2003.
711


712

Endnotes

Chapter 3
1. Letter to the Editor, Pittsburgh Post-Gazette, March 13, 1997.
2. Pittsburgh Post-Gazette, November 13, 2004.
3. Rita Healy, “Where You Will Live the Longest,” Health & Science, Time,
September 12, 2006.
4. “‘Get Tough’ Programs for Youths Critized,” The Boston Globe,
October 16, 2004.
5. Pittsburgh Post Gazette, November 17, 2004.
6. Emily F. Oster, “Witchcraft, Weather and Economic Growth in Renaissance
Europe,” Journal of Economic Perspectives, Winter 2004, posted
March 30, 2004.
7. “FDA: More Tests on Female Sexual Dysfunction Drug,” St. Augustine
Record, December 3, 2004.
8. Anabelle Garay, Associated Press, “As Orders Soar, Concerns Over Stun Guns
Grow,” November 30, 2004.
9. “Stress Found in Returning Soldiers,” Pittsburgh Post-Gazette, July 1, 2004.
10. [personal experience of the author, Glacier National Park, approx 2000.]
11. Robert Frost, “Happiness Makes Up in Height for What It Lacks in Length,”
1942. Albert Camus, unsourced.

12. Anita Srikameswaran, “Survey Find County Enjoys Good Health,” Pittsburgh
Post-Gazette, February 26, 2004.
13. Dennis Gilbert, “Hamilton College Youth and Guns Poll,” Hamilton College,
August 21, 2000.
14. “Data Found Lacking on Effects of Gun Control Efforts,” USA Today,
December 16, 2004.
15. Edison/Mitofsky, United States General Exit Poll, November 2, 2004.
16. Edison/Mitofsky, United States General Exit Poll, November 2, 2004.
17. “Majority Support for Gun Control; Majority Support Continuation of
National Firearms Registry,” Environics Research Group, February 21, 2003.
18. “Phantom Illness,” The Augusta Chronicle, November 1, 2004.
19. “Moderate Walking Helps the Mind Stay Sharper,” Pittsburgh Post-Gazette,
September 22, 2004.
20. “Couch Potato Nation,” Pittsburgh Post-Gazette, January 12, 1999.
21. “Study Forced Orphans to Stutter,” Seattle Times, June 11, 2001.
22. Anahad O’Connor, “The Claim: Bee Stings Can Be Treated by Scraping Out
Stingers,” The New York Times, May 30, 2006.
23. David Biello, “Washing Hands Reduces Moral Taint,” Scientific American,
September 7, 2006.
24. Bob Herbert, “Countdown to Execution No. 300,” The New York Times,
March 10, 2003.
25. Sandra Blakeslee, “Study Offers Surprise on Working of Body’s Clock,” The
New York Times, January 16, 1998.
26. “Piano Lessons Boost Math Scores,” Personal MD, March 18, 1999.
27. “When Your Hair’s a Real Mess, Your Self-Esteem is Much Less,” Pittsburgh
Post-Gazette, January 26, 2000.


Endnotes

28. Carey Hamilton, “How Healthy Is Our State for Kids? Study Will Tell,” The
Salt Lake Tribune, September 30, 2005.
29. Juliet Eilperin, “Study of Pesticides and Children Stirs Protests,” Washington
Post, October 30, 2004.
30. “Watching TV May Hurt Toddlers’ Attention Spans,” msnbc, April 5, 2004.
31. “Watching TV May Hurt Toddlers’ Attention Spans,” msnbc, April 5, 2004.
32. “Family Dinners Benefit Teens,” Briefs, Pittsburgh Post-Gazette,
August 26, 1997.
33. “Don’t Count Out Prostitutes,” The Philadelphia Inquirer, October 10, 2000.
34. “High Heels Can Drive You Literally Crazy,” The Citizen, July 25, 2005.
35. “Breast Milk Benefit,” The Pittsburgh Post-Gazette, September 9, 1998.
36. Fox Chase Pediatric, “Breast-Feeding Benefits Bolstered,” January 23, 2001.
37. Quaker Oats Company, Quaker Oats Oatmeal Product Label, 1999.
38. “Normal Teenagers are Not Ticking Time Bombs,” news-medical.net,
September 10, 2004.

Chapter 4
1. Chris Conway, “The DNA 200,” The New York Times, May 20, 2007.
2. David Carr, “New York Fiction, by the Numbers,” The New York Times,
June 1, 2004.
3. Marilyn vos Savant, “Ask Marilyn,” by Parade Magazine, February 29, 2004.
4. “Lab Still Most Popular Dog,” Pittsburgh Post-Gazette, February 18, 2004.
5. “Office Workers Give Away Passwords for a Chocolate Bar!,” M2 Presswire,
April, 2004, BNET (online).
6. “Study Indicates Racial Disparity in Traffic Stops,” The Pittsburgh PostGazette, April 22, 2002.
7. Eric Nagoumey, “A Big Professional Headache,” The New York Times,
December 2, 2003.
8. “Study: TV Shows Tend to be Bi-coastal,” USA Today, November 22, 2004.
9. Michael Roy and Nicholas Christenfeld, “Do Dogs Resemble Their Owners?”
Chance Magazine, March 31, 2004.

10. Matthew Wald, “F.A.A. Reviews Rules on Passenger Weight After Crash,”
The New York Times, January 28, 2003.
11. “Colleges Still Unsure How to Use New SAT,” Pittsburgh Post-Gazette,
February 25, 2007.
12. Fogel, Robert W., and Stanley L. Engerman. New Orleans Slave Sale Sample,
1804–1862 [Computer file]. Compiled by Robert W. Fogel and Stanley L.
Engerman, University of Rochester. ICPSR07423–v2. Ann Arbor, MI: Interuniversity Consortium for Political and Social Researcher [product and
distributor].
13. Johnston, Lloyd D., Jerald G. Bachman, Patrick M. O’Malley, and John E.
Schulenberg. Monitoring the Future: A Continuing Study of American Youth
(8th and 10th Grade Surveys), 2004 [Computer file]. Conducted by University of
Michigan, Institute for Social Research, Survey Research Center. ICPSR04263-v1.
Ann Arbor, MI: Inter-university Consortium for Political and Social Research.

713


714

Endnotes

14. Geoff Koch, “Study Confirms Dogs Can Sense Seizures,” The Dallas Morning
News, June 28, 2004.
15. Johnston, Lloyd D., Jerald G. Bachman, Patrick M. O’Malley, and John E.
Schulenberg. Monitoring the Future: A Continuing Study of American Youth
(8th and 10th Grade Surveys), 2004 [Computer file]. Conducted by University
of Michigan, Institute for Social Research, Survey Research Center.
ICPSR04263-v1. Ann Arbor, MI: Inter-university Consortium for Political and
Social Research.
16. Anahad O’Connor, “In Michigan, a Milestone for a Mouse Methuselah,” April

13, 2004.
17. Blair Tindall, “The Plight of the White-Tie Worker,” The New York Times,
Sunday, July 4, 2004.
18. “Food Statistics>Beer consumption (most recent) by country,” reported online
at />19. Nicholas Wade [for New York Times], “Remains Found of Downsized Human
Species,” Pittsburgh Post-Gazette, October 28, 2004.
20. J. Trinkaus, “Compliance with the Item Limit of the Food Supermarket
Express Checkout Lane: An Informal Look,” Psychological Reports, 73, no. 1
(August 1993): 105–6.
21. Mark Sherman [credited to Associated Press], “Caesarian Deliveries Hit U.S.
Record,” The Seattle Times, November 24, 2004.
22. “Antarctic Birds Use Scent to Find Their Mates,” USA Today, October 29,
2004 [credited to Associated Press].
23. Wines, Michael, and Sharon Lafraniere,“Hollowed Generation: Plunge in Life
Expectancy; Hut by Hut, AIDS Steals Life in a Southern Africa Town,” The
New York Times, November 28, 2004.
24. Deborah Solomon, “The Science of Second-Guessing,” interview, New York
Times, December 12, 2004.
25. Anthony Walton, “Review of ‘The State Boys Rebellion’ by Michael
D’Antonio,” The New York Times, June 27, 2004.
26. Gollop, J. B., and W. H. Marshall. “A Guide for Aging Duck Broods in the
Field, Mississippi Flyway Council Technical Section,” p. 14 Northern Prairie
Wildlife Research Center Home Page, 1954.

Chapter 5
1. “Study: Chewing Gum and CDs May Help Students Master Dental Anatomy,”
Global Health Nexus, NYU College of Dentistry, Winter 2004.
2. Luther Carpenter, “Job Redistribution a la Francaise,” Dissent Magazine
(online).
3. Lyric Wallwork Winik, “Films and hormones,” Parade Magazine,

October 10, 2004.
4. “Link Between Caffeine Consumption and High Blood Pressure Found in
Adolescents,” PsychCentral, April 29, 2004.
5. “Oh, Deer!,” Pittsburgh Post-Gazette, November 21, 2004.
6. Gina Kolata, “Dream Drug Too Good to Be True?,” The New York Times,
reported in The Pittsburgh Post-Gazette, December 5, 2004.


Endnotes

7. “Wrinkle Fighter Could Help Reduce Excessive Sweating” [attributed to The
Associated Press], Pittsburgh Post-Gazette, February 8, 2004.
8. Clifford Krauss, “Canada’s View on Social Issues is Opening Rifts with the
U.S.,” The New York Times, December 2, 2003.
9. Justin Bachman, “This & That: You Do What?!?,” The Pittsburgh PostGazette, July 12, 2004.
10. Lyric Wallwork Winik, “Make a Mess—and Money,” Parade Magazine,
March 6, 2005.
11. Steven R. Weisman, “Chart: The Other Troops in Iraq,” The New York Times,
November 21, 2004.
12. “Tight Ties Could Damage Eyesight,” BBC News (online), July 28, 2003.
13. “Study: Anti-Seizure Drug Reduces Drinking in Bipolar Alcoholics,” Bipolar
Central (online), January 6, 2005.
14. Eduardo Porter, “Values Gap: Where Playboy and ‘Will and Grace’ Reign,”
November 21, 2004.
15. Giron, D., D. Dunn, I. Hardy, and M. Strand, “Aggression by Polyembryonic
Wasp Soldiers Correlates with Kinship but not Resource Competition,”
Nature, 430 (5 August 2004): 676–79.
16. Jaime Holguin, “How to Talk to Dying Children,” CBS News (online),
September 15, 2004 [attributed to Associated Press].
17. “Pounds and Penance,” The Guardian, January 15, 2001.

18. Christopher Snowbeck, “Perspiration, Not Procreation,” Pittsburgh PostGazette, July 7, 2002.
19. “Life by the Numbers: What Do Americans Like?” [attributed to Associated
Press], St. Petersburg Times (online), December 8, 2004.
20. “Life by the Numbers: What Do Americans Like?” [attributed to Associated
Press], St. Petersburg Times (online), (accessed December 8, 2004).
21. Dan Lewerenz, “Exercise Beats Calcium at Boosting Girls’ Bones,” Pittsburgh
Post-Gazette [attributed to Associated Press], June 15, 2004.
22. Lee Bowman, “Too Few z’s May Result in Too Many Pounds,” Scripps
Howard News Service, www.sitnews.us, December 7, 2004.
23. Hull, Joseph, and Greg Langkamp, “Puget Sound Butter Clams Length v.
Width,” Quantitative Environmental Learning Project (QELP).
24. Lawrence Walsh, “A Complete Guide to the Region’s Slopes,” Pittsburgh
Post-Gazette, November 14, 2004.
25. Michael Janofsky, “E.P.A. Cuts Pollution Levels with Refinery Settlements,”
The New York Times, October 10, 2004.
26. Barbara White Stack, “Law to Increase Adoptions Results in More Orphans,”
Pittsburgh Post-Gazette, reported on seattlepi.com (accessed January 3, 2005).
27. Nick Wadhams, The Associated Press, “Cars Becoming Weapon of Choice,”
reported in Pittsburgh Post-Gazette, January 13, 2005.
28. Emily F. Oster, “Witchcraft, Weather and Economic Growth in Renaissance
Europe,” Journal of Economic Perspectives, Winter 2004, posted March 30,
2004.
29. Richard Bernstein, “Modern German Duty: The Obligation to Play,” The New
York Times, July 2, 2003.

715


716

Endnotes

30. Stacey Hirsh, “Sitting Is a Spreading Occupational Hazard,” The Baltimore
Sun, April 15, 2004.
31. Hal R. Varian, “Studies Find That for Men, It Pays to Be Married,”
International Herald Tribune, July 30, 2004.
32. Witte, Griff, and Nell Henderson, “Wealth Gap Widens for Blacks, Hispanics,”
The Washington Post, October 18, 2004.
33. “Busting the Nursery Rhymes,” Pittsburgh Post-Gazette, November 30, 2004.
34. Donald G. McNeil Jr., “Large Study on Mental Illness Finds Global
Prevalence,” The New York Times, June 2, 2004.
35. Piperno, D., E. Weiss, I. Holst, and D. Nadel, “Processing of Wild Cereal
Grains in the Upper Palaeolithic Revealed by Starch Grain Analysis,”
Nature, 430 (5 August 2004): 670–73.
36. C. Brown, “The Information Trail of the ‘Freshman 15’––A Systematic
Review of a Health Myth within the Research and Popular Literature,” Health
Information Libraries Journal, 25, no 1 (March 2008): 1–12.
37. John Heilprin, “Coral Reefs Less Healthy Now than 2 Years Ago,” Pittsburgh
Post-Gazette, December 7, 2004.
38. Hibell, B., B. Andersson, T. Bjarnason, A. Kokkevi, M. Morgan, and
A. Narusk, “The European School Survey Project on Alcohol and Drugs
(ESPAD),” 1995 Report.
39. Trinkaus, J., “An Informal Look at Use of Bakery Department Tongs and
Tissues,” Perceptual and Motor Skills, December 1998.
40. Mackenzie Carpenter, “Study Links Teen Sex, Suggestive TV Fare,”
Pittsburgh Post-Gazette [Reported in the Cleveland Plain Dealer],
September 9, 2004.
41. “The Best & Worst of Everything: Our Annual Year-End Roundup,” Parade
Magazine, December 26, 2004.
42. McKeganey, N., J. Norrie, “Association Between Illegal Drugs and Weapon

Carrying in Young People in Scotland: Schools’ Survey,” British Medical
Journal, 320 (April 8, 2000): 982–84.
43. Eric Nagourney, “Prevention: Harder Water and Longer Lives,” The New York
Times, January 27, 2004.
44. Eric Nagourney, “Power of Smell––Flavonoids Counter Reactive Oxygen in
Body. The Stronger an Onion Tastes, the More Likely It Is to Help Fight
Cancer and Other Diseases, Scientists at Cornell Have Found,” The Telegraph
of Calcutta, India, November 1, 2004.
45. Genaro C. Armas [Associated Press], “Life by the Numbers,”
SouthCoastTODAY.com, May 19, 2009.
46. “African AIDS Patients More Diligent in Taking Medicine Than in U.S.,”
Pittsburgh Post-Gazette, September 3, 2003.
47. “Warming Reducing Rice Yields,” Pittsburgh Post-Gazette, July 5, 2004.
48. “Drop in Temperatures Could Lower Ticket Prices, Too,” Pittsburgh PostGazette, January 13, 2005.
49. James Brooke, “Golfing Mongolia: A 2.3-Million-Yard par 11,880,” The New
York Times, July 4, 2004.
50. Paula Reed Ward, “PA Hunting Season Claimed 3 Lives,” Pittsburgh PostGazette, December 12, 2004.


Endnotes

Chapter 6
1. Brewer, P., and C. Wilcox, “Same-Sex Marriage and Civil Unions,” Public
Opinion Quarterly, 69, no. 4 (2005): 599–616.
2. John Houle, Cornerstone Communications Group, “Health & Safety Survey,”
American Nurses Association online, September 2001.
3. “Asides,” Pittsburgh Post-Gazette, July 4, 2004.
4. McKeganey, N., J. Norrie, “Association Between Illegal Drugs and Weapon
Carrying in Young People in Scotland: Schools’Survey,” British Medical
Journal, 320 (April 8, 2000): 982–84.

5. Byron Spice, “How Not to Catch a Spy: Use a Lie Detector,” Pittsburgh PostGazette, October 9, 2002.
6. “Sweating the Details,” Pittsburgh Post-Gazette, July 27, 2004.
7. “Ultrasound Improves Stroke Blood Clot Clearance,” Future Pundit online
news, November 18, 2004.
8. Dale Lawrence Pearlman, MD, “A Simple Treatment for Head Lice: Dry-On,
Suffocation-Based Pediculicide,” Pediatrics Online Journal, September 1,
2004.
9. John Houle, Cornerstone Communications Group, “Health & Safety Survey,”
American Nurses Association online, September 2001.
10. Xenia Montenegro, “Lifestyles, Dating and Romance: A Study of Midlife
Singles,” AARP Knowledge Management, September 2003.
11. “Taunts Cut Girls More than Sticks or Stones,” Pittsburgh Post-Gazette,
November 12, 2003.
12. David Carr, “New York Fiction, By the Numbers,” The New York Times,
June 1, 2004.
13. R. Trueb, “Association Between Smoking and Hair Loss: Another Opportunity
for Health Education Against Smoking?,” Dermatology, 206 (2003): 189–91.
14. “Fewer Drinks–––Fewer Gray Hairs,” Pittsburgh Post-Gazette,
February 20, 2008.
15. “Home Pregnancy Tests Reviewed,” Bandolier Journal (online), June 1999.

Chapter 7
1. Johnston, Lloyd D., Jerald G. Bachman, Patrick M. O’Malley, and John E.
Schulenberg, Monitoring the Future: A Continuing Study of American Youth
(8th- and 10th-Grade Surveys), 2004 [Computer file]. Conducted by
University of Michigan, Institute for Social Research, Survey Research Center.
ICPSR04263-v1. Ann Arbor, MI: Inter-university Consortium for Political and
Social Research [producer and distributor], 2005–12–15.
doi:10.3886/ICPSR04263.
2. Axinn, William G., Arland Thornton, Jennifer S. Barber, Susan A. Murphy,

Dirgha Ghimire, Thomas Fricke, Stephen Matthews, Dharma Dangol, Lisa
Pearce, Ann Biddlecom, Sundar Shrehtha, and Douglas Massey, Chitwan
Valley [Nepal] Family Study: Changing Social Contexts and Family
Formation [Computer file]. ICPSR04538-v3. Ann Arbor, MI: Inter-university
Consortium for Political and Social Research [distributor], 2009–05–13.
doi:10.3886/ICPSR04538.

717


718

Endnotes

3. Axinn, William G., Arland Thornton, Jennifer S. Barber, Susan A. Murphy,
Dirgha Ghimire, Thomas Fricke, Stephen Matthews, Dharma Dangol, Lisa
Pearce, Ann Biddlecom, Sundar Shrehtha, and Douglas Massey, Chitwan
Valley [Nepal] Family Study: Changing Social Contexts and Family
Formation [Computer file]. ICPSR04538-v3. Ann Arbor, MI: Inter-university
Consortium for Political and Social Research [distributor], 2009–05–13.
doi:10.3886/ICPSR04538.
4. Johnston, Lloyd D., Jerald G. Bachman, Patrick M. O’Malley, and John E.
Schulenberg, Monitoring the Future: A Continuing Study of American Youth
(8th- and 10th-Grade Surveys), 2004 [Computer file]. Conducted by
University of Michigan, Institute for Social Research, Survey Research Center.
ICPSR04263-v1. Ann Arbor, MI: Inter-university Consortium for Political and
Social Research [producer and distributor], 2005-12-15.
doi:10.3886/ICPSR04263.
5. Grand Canyon National Park Northern Arizona Tourism Study, April 2005.
6. Maggie Fox, “Half of Bankruptcy Due to Medical Bills––U.S. Study,”

Reuters, February 2, 2005.
7. Habler, H. J., W. Janig, M. Krummel, and O. A. Peters, “Reflex Patterns in
Postganglionic Neurons Supplying Skin and Skeletal Muscle of the Rat
Hindlimb,” Journal of Neurophysiology, Vol 72, Issue 5 2222–2236.
8. “Tall Enough?,” Pittsburgh Post-Gazette, November 4, 2003.
9. Axinn, William G., Arland Thornton, Jennifer S. Barber, Susan A. Murphy,
Dirgha Ghimire, Thomas Fricke, Stephen Matthews, Dharma Dangol, Lisa
Pearce, Ann Biddlecom, Sundar Shrehtha, and Douglas Massey, Chitwan
Valley [Nepal] Family Study: Changing Social Contexts and Family
Formation [Computer file]. ICPSR04538-v3. Ann Arbor, MI: Inter-university
Consortium for Political and Social Research [distributor], 2009–05–13.
doi:10.3886/ICPSR04538.

Chapter 8
1. Veronica Torrejon, “U.S. Teens share Parents’ Religion, Survey Finds,” The
Los Angeles Times, February 26, 2005.
2. Veronica Torrejon, “U.S. Teens Share Parents’ Religion, Survey Finds,” The
Los Angeles Times, February 26, 2005.
3. Skrbinsek, A., and A. Bath, “Attitudes of Rural and Urban Public Toward
Wolves in Croatia,” Conservation and Management of Wolves in Croatia,
2005.
4. “Criminal Pasts Cited for Many City School Bus Drivers,” Pittsburgh PostGazette, November 19, 2003.
5. L.A. Johnson, “Passing Along (or Recycling) Unwanted Gifts Can Be Fraught
with Peril,” Pittsburgh Post-Gazette, December 25, 2004.
6. Boy, E. N. Bruce, and H. Delgado, “Birth Weight and Exposure to Kitchen
Wood Smoke During Pregnancy in Rural Guatemala,” Environmental Health
Perspectives, no. 1 (January 2002): 109–14.


Endnotes

Chapter 9
1. “Does Anybody Really Know Quelle Heure Est-il?,” Pittsburgh Post-Gazette,
February 20, 2005.
2. “Criminal Pasts Cited for Many City School Bus Drivers,” Pittsburgh PostGazette, November 19, 2003.
3. “The Comfort of a Familiar Scent,” Pittsburgh Post-Gazette, June 1, 2005.
4. Robert Barr [Associated Press], “Princess Diana Remembered,” reported on an
ABC Action News website (accessed August 31, 2007).
5. Trockel, Mickey, Michael Barnes, and Dennis Egget, “Health Related
Variables and Academic Performance among First-Year College Students:
Implications for Sleep and Other Behaviors,” Journal of American College
Health, 49, no 3 (2000): 125–31.
6. Daniel J. DeNoon, “Sleep Face Down for Lower Blood Pressure,” WebMD
Health News, October 11, 2004.
7. Kirton, A., E. Wirrell, J. Zhang, and L. Hamiwka, “Seizure-Alerting and
-Response Behaviors in Dogs Living with Epileptic Children,” Neurology, 62
(2004): 2303–5.
8. John Hanna [Associated Press], “Topeka Voters Reject Ordinance Repeal,
Anti-Discrimination Law Will Stand,” reported online in Common Ground
Common Sense, March 1, 2005.
9. “What Readers Think About Reading–––a 1999 Survey,” The Bookseller,
November 19, 1999; reported online by the National Reading Campaign.
10. “A Friendly Word Is the Best Way of Turning a Book into a Bestseller,”
Independent, March 3, 2005; reported online by the National Reading
Campaign.
11. Statement of Dr. Kathleen McChesney, Office of Media Relations, United
States Conference of Catholic Bishops, February 18, 2005.
12. “13th Annual ‘Attitudes in the American Workplace’ Poll conducted by Harris
Interactive for The Marlin Company Results,” 2007.
13. “Antibiotic Resistance Puzzle,” Pittsburgh Post-Gazette, February 18, 2004.

14. L.A. Johnson, “Passing Along (or Recycling) Unwanted Gifts Can Be Fraught
with Peril,” Pittsburgh Post-Gazette, December 25, 2004.
15. S. Kazakova et al., “A Clone of Methicillin-Resistant Staphylococcus Aureus
Among Professional Football Players,” New England Journal of Medicine,
352 (February 3, 2005): 468–75.
16. Livingstone, M. S., and B. R. Conway, “Was Rembrandt Stereoblind?” New
England Journal of Medicine, 351 (September 16, 2004): 1264.
17. “Hospital Chiefs Wary of Mandate on Error Reports,” Pittsburgh Post-Gazette,
March 16, 2005.
18. Ben Feller [Associated Press], “Survey: Most Young Adults Value College;
Nonetheless, Many Fall Short of Getting There or Graduating,” February 8,
2005.
19. “65 Percent of Children Have Had an Imaginary Companion,” The Medical
News, December 6, 2004.
20. “First Amendment No Big Deal, Students Say,” MSNBC (online) [Associated
Press], January 31, 2005.

719


720

Endnotes

21. Maxim Kelly, “Rude Health: Sound Warning on Your Lungs,” The Sunday
Business Post Online, June 26, 2005.
22. “Contraception Shots Work in Male Monkeys,” Pittsburgh Post-Gazette,
November 12, 2004.
23. “Obesity Rampant in NFL, Study Says,” The Daughtry Times [Associated
Press], March 1, 2005.

24. “Kids Overdo Headache Meds,” Pittsburgh Post-Gazette, June 15, 2004.
25. “Full Moon Exerts No Pull on Frequency of Epileptic Seizures,” Bio-Medicine
(online), May 25, 2004.
26. “Half of Moms Are Unaware of Children Having Sex,” Pittsburgh PostGazette, September 5, 2002.
27. Sandra G. Boodman, “New Rules for Safer Surgery,” The Washington Post,
[reported in Post-Gazette Now], July 13, 2004.
28. “Antibiotic Resistance Puzzle,” Pittsburgh Post-Gazette, February 18, 2004.
29. Young, Donn, and Erinn Hade, “Holidays, Birthdays, and Postponement of
Cancer Death,” The Journal of the American Medical Association (JAMA),
292, no. 24 (December 22/29, 2004).
30. “Study Proves Number Bias in UK Lottery,” usamega.com [Archived lottery
news website] (accessed December 11, 2004).
31. Daniel J. DeNoon, “Dairy Food No Magic Bullet for Weight Loss,” Fox News
(online), Friday, November 19, 2004.
32. Byron Spice, “How Not to Catch a Spy: Use a Lie Detector,” Pittsburgh PostGazette, October 9, 2002.
33. “Amgen Will Stop Providing Parkinson’s Drug,” AP Online, February 13,
2005.
34. Roy, Michael, and Nicholas Christenfeld, “Do Dogs Resemble Their
Owners?,” Chance Magazine, March 31, 2004.
35. “Federal Intervention in Schiavo Case Prompts Broad Public Disapproval,”
ABC News (online), Monday, March 21, 2005.
36. “Antibiotic Resistance Puzzle,” Pittsburgh Post-Gazette, February 18, 2004.
37. Jean Koppen,“Medical Uses of Marijuana: Opinions of U.S. Residents 45+,”
AARP Policy & Research, December 2004.
38. “2004 a Bad Year for the Grizzly Bear,” Pittsburgh Post-Gazette,
December 20, 2004.
39. Nick Santangelo, “Courtship in the Monogamous Convict Cichlid; What Are
Individuals Saying to Rejected and Selected Mates?” Animal Behaviour, 68,
no. 1, (January 2005): 143–49.
40. Nick Santangelo, “Courtship in the Monogamous Convict Cichlid; What Are

Individuals Saying to Rejected and Selected Mates?” Animal Behaviour, 68,
no. 1, (January 2005): 143–49.
41. Chio, A., G. Benzi, M. Dossenal, R. Mutani, and G. Mora, “Severely Increased
Risk of Amyotrophic Lateral Sclerosis Among Italian Professional Football
Players,” Brain, January 5, 2005.
42. Persons, Matthew, and George Uetz, “Sexual Cannibalism and Mate Choice
Decisions in Wolf Spiders: Influence of Male Size and Secondary Sexual
Characters,” Animal Behavior, 69, no. 1 (January 2005): 83–94.