**PART I: **Exploring Data 1

**CHAPTER 1 **Picturing Distributions with Graphs 3

Individuals and variables / 3

Categorical variables: pie charts and bar graphs / 5

Quantitative variables: histograms / 10

Interpreting histograms / 12

Quantitative variables: stemplots / 16

Time plots / 19

**CHAPTER 2 D**escribing Distributions with Numbers 29

Measuring center: the mean / 29

Measuring center: the median / 31

Comparing the mean and the median / 32

Measuring spread: the quartiles / 33

The five-number summary and boxplots / 34

Measuring spread: the standard deviation / 37

Choosing measures of center and spread / 39

Using technology / 40

Organizing a statistical problem / 40

**CHAPTER 3 **The Normal Distributions 51

Density curves / 51

Describing density curves / 54

Normal distributions / 55

The 68-95-99.7 rule / 57

The standard Normal distribution / 59

Finding Normal proportions / 61

Using the standard Normal table / 62

Finding a value given a proportion / 65

**CHAPTER 4 **Scatterplots and Correlation 73

Explanatory and response variables / 73

Displaying relationships: scatterplots / 74

Interpreting scatterplots / 76

Measuring linear association: correlation / 79

Facts about correlation / 80

**CHAPTER 5 **Regression 91

Regression lines / 91

The least-squares regression line / 94

Using technology / 95

Facts about least-squares regression / 97

Residuals / 98

Influential observations / 101

Cautions about correlation and regression / 103

Association does not imply causation / 105

**CHAPTER 6 **Exploring Data: Part I Review 115

Part I Summary / 115

Review Exercises / 116

Supplementary Exercises / 121

**PART II: **From Exploration to Inference 127

**CHAPTER 7 **Producing Data: Sampling 129

Population versus sample / 129

How to sample badly / 131

Simple random samples / 132

Inference about the population / 136

Cautions about sample surveys / 137

**CHAPTER 8 **Producing Data: Experiments 145

Observation versus experiment / 145

Subjects, factors, treatments / 147

How to experiment badly / 149

Randomized comparative experiments / 150

The logic of randomized comparative experiments / 153

Cautions about experimentation / 154

Matched pairs designs / 156

**CHAPTER 9 **Introducing Probability 163

The idea of probability / 164

Probability models / 166

Probability rules / 168

Discrete probability models / 171

Continuous probability models / 172

Random variables / 176

iv ** Starred material is not required for later parts of the text.*

**CHAPTER 10 **Sampling Distributions 183

Parameters and statistics / 183

Statistical estimation and the law of large numbers / 184

Sampling distributions / 187

The mean and standard deviation of ¯*x */ 189

The central limit theorem / 190

**CHAPTER 11** General Rules of Probability* 199

Independence and the multiplication rule / 199

The general addition rule / 203

Conditional probability / 205

The general multiplication rule / 20

Tree diagrams / 208

**CHAPTER 12 **Binomial Distributions* 217

The binomial setting and binomial distributions / 217

Binomial distributions in statistical sampling / 218

Binomial probabilities / 219

Binomial mean and standard deviation / 221

The Normal approximation to binomial distributions / 223

**CHAPTER 13 **Introduction to Inference 231

The reasoning of statistical estimation / 232

Confidence intervals for a population mean / 235

The reasoning of statistical tests / 238

Stating hypotheses / 241

*P*-values / 242

Tests for a population mean / 245

Statistical significance / 248

**CHAPTER 14 **Thinking about Inference 257

Conditions for inference in practice / 257

How confidence intervals behave / 261

Sample size for confidence intervals / 263

How significance tests behave / 264

**CHAPTER 15 **From Exploration to Inference: Part II Review 273

Part II Summary / 273

Review Exercises / 275

Supplementary Exercises / 279

Optional Exercises / 281

**PART III: **Inference about Variables 283

**CHAPTER 16 **Inference about a Population Mean 285

Conditions for inference about a mean / 285

The *t *distributions / 286

The one-sample *t *confidence interval / 288

The one-sample *t *test / 291

Using technology / 293

Matched pairs *t *procedures / 295

Robustness of *t *procedures / 297

**CHAPTER 17 **Two-Sample Problems 307

Comparing two population means / 308

Two-sample *t *procedures / 310

Using technology / 315

Robustness again / 317

**CHAPTER 18 **Inference about a Population Proportion 327

The sample proportion ˆ*p */ 328

Large-sample confidence intervals for a proportion / 330

Choosing the sample size / 332

Significance tests for a proportion / 334

**CHAPTER 19 **Comparing Two Proportions 341

Two-sample problems: proportions / 341

The sampling distribution of a difference between proportions / 342

Large-sample confidence intervals form comparing proportions / 343

Using technology / 344

Significance tests for comparing proportions / 346

**CHAPTER 20 **Inference about Variables: Part III Review 353

Statistics in Outline / 353

Part III Summary / 354

Review Exercises / 356

Supplementary Exercises / 359

**PART IV: **Inference about Relationships 363

**CHAPTER 21 **Two Categorical Variables: The Chi-Square Test 365

Two-way tables / 365

Is there a relationship? Expected cell counts / 370

The chi-square test / 372

Data analysis for chi-square / 374

Another use of the chi-square test / 378

The chi-square distributions / 380

The chi-square test for goodness of fit / 382

**CHAPTER 22 **Inference for Regression 393

Conditions for regression inference / 395

Estimating the parameters / 396

Using technology / 399

Testing the hypothesis of no linear relationship / 401

Testing lack of correlation / 403

Confidence intervals for the regression slope / 404

Inference about prediction / 405

Checking the conditions for inference / 408

**CHAPTER 23 **One-Way Analysis of Variance:

Comparing Several Means 421

The analysis of variance *F *test / 423

Using technology / 425

The idea of analysis of variance / 429

Conditions for ANOVA / 431

*F *distributions and degrees of freedom / 435

**NOTES AND DATA SOURCES** / 445

**TABLES** / 463

TABLE A Standard Normal Probabilities / 464

TABLE B Random Digits / 466

TABLE C *t *Distribution Critical Values / 467

TABLE D Chi-Square Distribution Critical Values / 468

**ANSWERS TO SELECTED EXERCISES** / 469

*INDEX / 495*

Additional Material (available on the *Essential Statistics *CD and Web site www.whfreeman.com/essentialstats)

**CHAPTER 24 **Nonparametric Tests

Comparing two samples: the Wilcoxon rank sum test

The Normal approximation for *W*

Using technology

What hypotheses does Wilcoxon test?

Dealing with ties in rank tests

Matched pairs: the Wilcoxon signed rank test

The Normal approximation for *W*+

Dealing with ties in the signed rank test

Commentary: Data Ethics

Applets for Interactive Learning