1.  Descriptive Statistics 1
    1.1 Measures of Central Tendency 3
    1.2 The Mean of Means 9
    1.3 The Mode’s Location 13
    1.4 The Standard Deviation 15
            Recommended Reading 18
2.  Distributional Shape 19
    2.1 The Shape of the Normal Curve 21
    2.2 Skewed Distributions and Measures of Central Tendency 25
    2.3 Standard Scores and Normality 29
    2.4 Rectangular Distributions and Kurtosis 33
            Recommended Reading 37
3.  Bivariate Correlation 39
    3.1 Correlation Coefficients 41
    3.2 Correlation and Causality 45
    3.3 The Effect of a Single Outlier on Pearson’s r 49
    3.4 Relationship Strength and r 55
    3.5 The Meaning of r = 0 59
            Recommended Reading 63
4.  Reliability and Validity 65
    4.1 Statistical Indices of Reliability and Validity 67
    4.2 Interrater Reliability 71
    4.3 Cronbach’s Alpha and Unidimensionality 77
    4.4 Range Restriction and Predictive Validity 83
            Recommended Reading 87
5.  Probability 89
    5.1 The Binomial Distribution and N 91
    5.2 A Random Walk with a Perfectly Fair Coin 95
    5.3 Two Goats and a New Car 99
    5.4 Identical Birthdays 103
    5.5 The Sum of an Infinite Number of Numbers 107
    5.6 Being Diagnosed With a Rare Disease 111
    5.7 Risk Ratios and Odds Ratios 115
            Recommended Reading 119
6.  Sampling 121
    6.1 The Character of Random Samples 123
    6.2 Random Replacements When Sampling 127
    6.3 Precision and the Sampling Fraction 131
    6.4 Matched Samples 135
    6.5 Finite Versus Infinite Populations 139
            Recommended Reading 143
7.  Estimation 145
    7.1 Interpreting a Confidence Interval 147
    7.2 Overlapping Confidence Intervals 151
    7.3 The Mean ± the Standard Error 155
    7.4 Confidence Intervals and Replication 159
            Recommended Reading 163
8.  Hypothesis Testing 165
    8.1 Alpha and Type I Error Risk 167
    8.2 The Null Hypothesis 171
    8.3 Disproving Ho 175
    8.4 The Meaning of p 179
    8.5 Directionality and Tails 183
    8.6 The Relationship Between Alpha and Beta Errors 189
            Recommended Reading 193
9.  t-Tests Involving One or Two Means 195
    9.1 Correlated t-Tests 197
    9.2 The Difference Between Two Means If p < .0001 201
    9.3 The Robustness of a t-Test When n1 = n2 205
            Recommended Reading 208
10.  ANOVA and ANCOVA 209
    10.1 Pairwise Comparisons 211
    10.2 The Cause of a Significant Interaction 215
    10.3 Equal Covariate Means in ANCOVA 219
            Recommended Reading 223
11.  Practical Significance, Power, & Effect Size 225
    11.1 Statistical Versus Practical Significance 227
    11.2 A Priori and Post Hoc Power 231
    11.3 Eta Squared and Partial Eta Squared 237
            Recommended Reading 241
12.  Regression 243
    12.1 Comparing Two r’s;Comparing Two b’s 245
    12.2 R2 249
    12.3 Predictor Variables That Are Uncorrelated With Y 253
    12.4 Beta Weights 257
            Recommended Reading 261
Appendix A:

        Citations for Material Referenced in Preface 263
Appendix B:

        References for Quotations Presented in the Sections 265
        Entitled “Evidence That This Misconception Exists”
Subject Index 279
Author Index 285
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