Title Details

Preface V

Acknowledgments VII

1 Introduction 3

1.1 Why Study Statistics? 4

1.2 What Is Statistics? 4

1.3 More About Inferential Statistics 6

1.4 Three Types Of Data 9

1.5 Levels Of Measurement 10

1.6 Types Of Variables 14

1.7 How To Use This Book 19

Summary20

Important Terms 21

Review Questions 21

Part 1 Descriptive Statistics: Organizing And Summarizing Data 25

2 Describing Data With Tables And Graphs 27

Tables (Frequency Distributions) 28

2.1 Frequency Distributions For Quantitative Data 28

2.2 Guidelines 29

2.3 Outliers 34

2.4 Relative Frequency Distributions 35

2.5 Cumulative Frequency Distributions 36

2.6 Frequency Distributions For Qualitative (Nominal) Data 38

2.7 Interpreting Distributions Constructed By Others 39

Graphs 40

2.8 Graphs For Quantitative Data 40

2.9 Typical Shapes 45

2.10 A Graph For Qualitative (Nominal) Data 47

2.11 Misleading Graphs 48

2.12 Doing It Yourself 50

Summary 50

Important Terms 52

Review Questions 53

3 Describing Data With Averages 57

3.1 Mode 58

3.2 Median 59

3.3 Mean 61

3.4 Which Average? 63

3.5 Averages For Qualitative And Ranked Data 66

Summary 68

Important Terms 68

Key Equation 69

Review Questions 69

4 Describing Variability 73

4.1 Intuitive Approach 74

4.2 Range 76

4.3 Variance 76

4.4 Standard Deviation  77

4.5 Details: Standard Deviation 82

4.6 Degrees Of Freedom(Df) 90

4.7 Interquartile Range (Iqr) 92

4.8  Measures Of Variability For Qualitative  And Ranked Data  93

Summary 93

Important Terms 94

Key Equations 95

Review Questions 95

5  Normal Distributions And Standard (Z)  Scores 99

5.1 The Normal Curve 101

5.2 Z Scores 103

5.3 Standard Normal Curve 104

5.4 Solving Normal Curve Problems 107

5.5 Finding Proportions 108

5.6 Finding Scores 114

5.7 More About Z Scores 119

Summary 122

Important Terms 123

Key Equations 123

Review Questions 123

6 Describing Relationships: Correlation 127

6.1 An Intuitive Approach 128

6.2 Scatterplots 130

6.3  A Correlation Coefficient For Quantitative  Data: R  133

6.4 Details: Computation Formula For R 141

6.5 Outliers Again 143

6.6  Other Types Of Correlation  Coefficients 144

6.7 Computer Output 144

Summary 148

Important Terms 149

Key Equations 149

Review Questions 149

7 Regression 153

7.1 Two Rough Predictions 154

7.2 A Regression Line 155

7.3 Least Squares Regression Line 157

7.4 Standard Error Of Estimate, Sy|X 161

7.5 Assumptions 164

7.6  Interpretation Of  

7.7 Multiple Regression Equations 164

7.8 Regression Toward The Mean 165

Summary 167

Important Terms 168

Key Equations 168

Review Questions 168

Part 2 Inferential Statistics: Generalizing Beyond Data 171

8 Populations, Samples, And Probability 173

Populations And Samples 174

8.1 Populations 174

8.2 Samples 175

8.3 Random Sampling 176

8.4 Tables Of Random Numbers 177

8.5 Random Assignment Of Subjects 179

8.6 Surveys Or Experiments? 180

Probability 181

8.7 Definition 181

8.8 Addition Rule 182

8.9 Multiplication Rule 183

8.10 Probability And Statistics 186

Summary 188

Important Terms 188

Key Equations 189

Review Questions 189

9 Sampling Distribution Of The Mean 193

9.1 What Is A Sampling Distribution? 194

9.2 Creating A Sampling Distribution  From Scratch  195

9.3 Some Important Symbols 197

9.4 Mean Of All Sample Means () 199

9.5 Standard Error Of The Mean () 200

9.6 Shape Of The Sampling Distribution 202

9.7 Other Sampling Distributions 204

Summary 205

Important Terms 205

Key Equations 205

Review Questions 206

10 Introduction To Hypothesis Testing: TheZ Test 209

10.1 Testing A Hypothesis About Sat Scores 210

10.2 Z Test For A Population Mean 212

10.3 Step-By-Step Procedure 214

10.4 Statement Of The Research Problem 214

10.5 Null Hypothesis (H0) 215

10.6 Alternative Hypothesis (H1) 216

10.7 Decision Rule 217

10.8 Calculations  218

10.9 Decision 218

10.10   Interpretation 219

Summary 220

Important Terms 221

Key Equations 221

Review Questions 221

11 More About Hypothesis Testing 225

11.1 Why Hypothesis Tests? 226

11.2 Strong Or Weak Decisions 228

11.3 One-Tailed And Two-Tailed Tests 229

11.4 Choosing A Level Of Significance (a) 233

11.5 Testing A Hypothesis About Vitamin C 235

11.6 Four Possible Outcomes 235

11.7 If H0 Really Is True 238

11.8 If H0 Really Is False Because Of A Large Effect 239

11.9 If H0 Really Is False Because Of A Small Effect 242

11.10 Influence Of Sample Size 243

11.11 Power And Sample Size 246

Summary 249

Important Terms 251

Review Questions 251

12 Estimation (Confidence Intervals) 255

12.1 Point Estimate For m 256

12.2 Confidence Interval (Ci) For m 256

12.3 Interpretation Of A Confidence Interval 260

12.4 Level Of Confidence 261

12.5 Effect Of Sample Size 262

12.6 Hypothesis Tests Or Confidence Intervals? 263

12.7 Confidence Interval For Population  Percent 263

Summary 265

Important Terms 266

Key Equation 266

Review Questions 266

13T Test For One Sample 269

13.1 Gas Mileage Investigation 270

13.2 Sampling Distribution Of T 270

13.3 T Test 274

13.4 Common Theme Of Hypothesis Tests 275

13.5 Reminder About Degrees Of Freedom  275

13.6 Details: Estimating The Standard Error  275

13.7 Details: Calculations For The T Test 276

13.8 Confidence Intervals For M Based On T 278

13.9 Assumptions 279

Summary 280

Important Terms 280

Key Equations 280

Review Questions 280

14T Test For Two Independent Samples 285

14.1 Epo Experiment 286

14.2 Statistical Hypotheses 287

14.3 Sampling Distribution Of   289

14.4 T Test 91

14.5 Details: Calculations For The T Test 292

14.6 P-Values 296

14.7 Statistically Significant Results 299

14.8 Estimating Effect Size: Point Estimates And Confidence Intervals 300

14.9 Estimating Effect Size: Cohen’s D 303

14.10  Meta-Analysis

14.11 Reports In The Literature  306

14.12 Assumptions 308

14.13 Computer Output 308

Summary 309

Important Terms 310

Key Equations 310

Review Questions 311

15T Test For Two Related Samples  (Repeated Measures) 315

15.1 Epo Experiment With Repeated Measures 316

15.2 Statistical Hypotheses 319

15.3 Sampling Distribution Of  320

15.4 T Test 320

15.5 Details: Calculations For The T Test 321

15.6 Estimating Effect Size 324

15.7 Assumptions 326

15.8 Overview: Three T Tests For Population Means 326

15.9 T Test For The Population Correlation Coefficient, r 329

Summary 331

Important Terms 332

Key Equations 332

Review Questions 333

16 Analysis Of Variance (One Factor) 337

16.1 Testing A Hypothesis About Sleep Deprivation  And Aggression 338

16.2 Two Sources Of Variability 340

16.3 F Test 342

16.4 Details: Variance Estimates 344

16.5 Details: Mean Squares (Ms) And  The F Ratio 350

16.6 Table For The F Distribution 352

16.7 Anova Summary Tables 353

16.8 F Test Is Nondirectional 355

16.9 Estimating Effect Size 355

16.10 Multiple Comparisons 358

16.11 Overview: Flow Chart For Anova 362

16.12 Reports In The Literature 362

16.13 Assumptions 364

16.14 Computer Output 364

Summary 364

Important Terms 366

Key Equations 366

Review Questions 366

17 Analysis Of Variance (Repeated Measures) 371

17.1 Sleep Deprivation Experiment With  Repeated Measures 372

17.2 F Test 373

17.3 Two Complications 375

17.4 Details: Variance Estimates 375

17.5  Details: Mean Square (Ms) And  The F Ratio 379

17.6 Table For The F Distribution 381

17.7 Anova Summary Tables 381

17.8 Estimating Effect Size 383

17.9 Multiple Comparisons 384

17.10 Reports In The Literature 386

17.11 Assumptions 387

Summary 387

Important Terms 388

Key Equations 388

Review Questions 388

18 Analysis Of Variance (Two Factors) 393

18.1 A Two-Factor Experiment: Responsibility In Crowds 394

18.2 Three F Tests 397

18.3 Interaction 398

18.4 Details: Variance Estimates  402

18.5 Details: Mean Squares (Ms) And F Ratios  406

18.6 Table For The F Distribution 408

18.7 Estimating Effect Size 408

18.8 Multiple Comparisons 409

18.9 Simple Effects 410

18.10   Overview: Flow Chart For Two-Factor Anova 414

18.11  Reports In The Literature 415

18.12 Assumptions 416

18.13 Other Types Of Anova 416

Summary 417

Important Terms 417

Key Equations 417

Review Questions 418

19 Chi-Square (c2) Test For Qualitative (Nominal) Data 423  

One-Variable c2 Test 424

19.1 Survey Of Blood Types 424

19.2 Statistical Hypotheses 424

19.3 Details: Calculating c2 425

19.4 Table For The c 2 Distribution 428

19.5 c2 Test 428

Two-Variable c2 Test 431

19.6 Lost Letter Study 431

19.7 Statistical Hypotheses 432

19.8 Details: Calculating c2 433

19.9 Table For The c2 Distribution 434

19.10 c2 Test 436

19.11 Estimating Effect Size 437

19.12 Odds Ratios 438

19.13 Reports In The Literature 440

19.14 Some Precautions 441

19.15 Computer Output 442

Summary 443

Important Terms 443

Key Equations 443

Review Questions 444

20 Tests For Ranked (Ordinal) Data 449

20.1 Use Only When Appropriate 450

20.2 A Note On Terminology 450

20.3 Mann-Whitney U Test (Two Independent Samples) 451

20.4 Wilcoxon T Test (Two Related Samples) 456

20.5 Kruskal-Wallis H Test (Three Or  More Independent Samples) 460

20.6 General Comment: Ties 464

Summary 464

Important Terms 465

Review Questions 465

21 Postscript: Which Test? 469

21.1 Descriptive Or Inferential Statistics? 470

21.2 Hypothesis Tests Or Confidence Intervals? 470

21.3 Quantitative Or Qualitative Data? 472

21.4 Distinguishing Between The Two Types Of Data 472

21.5 One, Two, Or More Groups? 473

21.6 Concluding Comments 474

Review Questions 474

Appendices 479

A Math Review 479

B Answers To Selected Questions 487

C Tables 529

D Glossary 543

Photo Credits 550

Index 551