List of Figures |
|
xi | |
List of Tables |
|
xii | |
Preface |
|
xvi | |
|
|
xvii | |
|
What is New in this Edition? |
|
|
xvii | |
|
Formulae and Calculations |
|
|
xvii | |
|
|
xviii | |
|
The pwr2ppl Companion Package |
|
|
xviii | |
Acknowledgments |
|
xx | |
1 What is Power? Why is Power Important? |
|
1 | (17) |
|
Review of Null Hypothesis Significance Testing |
|
|
1 | (1) |
|
Effect Sizes and Their Interpretation |
|
|
2 | (1) |
|
|
3 | (3) |
|
Central and Noncentral Distributions |
|
|
6 | (2) |
|
Misconceptions about Power |
|
|
8 | (1) |
|
Empirical Reviews of Power |
|
|
9 | (1) |
|
Consequences of Underpowered Studies |
|
|
10 | (1) |
|
Overview of Approaches to Determining Effect Size for Power Analysis |
|
|
11 | (3) |
|
Post Hoc Power (a.k.a. Observed or Achieved Power) |
|
|
14 | (2) |
|
|
16 | (1) |
|
|
17 | (1) |
2 Chi Square and Tests for Proportions |
|
18 | (16) |
|
|
18 | (1) |
|
|
19 | (1) |
|
|
19 | (1) |
|
Example 2.1: 2 x 2 Test of Independence |
|
|
20 | (6) |
|
Example 2.2: 2 x 2 Chi Square Test for Independence Using R |
|
|
26 | (1) |
|
Example 2.3: Other x 2 Tests |
|
|
27 | (1) |
|
Example 2.4: General Effect Size-Based Approaches Using R |
|
|
27 | (1) |
|
Tests for Single Samples and Independent Proportions |
|
|
28 | (1) |
|
Example 2.5: Single Sample Comparison |
|
|
29 | (2) |
|
Example 2.6: Independent Proportions Comparison |
|
|
31 | (1) |
|
|
32 | (1) |
|
|
33 | (1) |
3 Independent Samples and Paired t-tests |
|
34 | (20) |
|
|
34 | (1) |
|
|
35 | (1) |
|
|
36 | (2) |
|
A Note about Effect Size for Two-Group Comparisons |
|
|
38 | (1) |
|
Example 3.1: Comparing Two Independent Groups |
|
|
39 | (3) |
|
Example 3.2: Power for Independent Samples t using R |
|
|
42 | (1) |
|
Example 3.3: Paired t-test |
|
|
43 | (1) |
|
Example 3.4: Power for Paired t using R |
|
|
44 | (1) |
|
Example 3.5: Power from Effect Size Estimate |
|
|
44 | (1) |
|
Dealing with Unequal Variances, Unequal Sample Sizes, and Violation of Assumptions |
|
|
45 | (4) |
|
Example 3.6: Unequal Variances and Unequal Sample Sizes |
|
|
49 | (3) |
|
|
52 | (1) |
|
|
53 | (1) |
4 Correlations and Differences between Correlations |
|
54 | (15) |
|
|
54 | (1) |
|
|
54 | (1) |
|
|
55 | (1) |
|
Example 4.1: Zero-order Correlations |
|
|
55 | (2) |
|
Comparing Two Independent Correlations |
|
|
57 | (1) |
|
Example 4.2: Comparing Independent Correlations |
|
|
58 | (2) |
|
Comparing Two Dependent Correlations (One Variable in Common) |
|
|
60 | (1) |
|
Example 4.3: Comparing Dependent Correlations, One Variable in Common |
|
|
61 | (2) |
|
Comparing Two Dependent Correlations (No Variables in Common) |
|
|
63 | (1) |
|
Example 4.4: Comparing Dependent Correlations, No Variables in Common |
|
|
64 | (3) |
|
Note on Effect Sizes for Comparing Correlations |
|
|
67 | (1) |
|
|
67 | (1) |
|
|
68 | (1) |
5 Between Subjects ANOVA (One and Two Factors) |
|
69 | (19) |
|
|
69 | (1) |
|
|
69 | (1) |
|
Omnibus Versus Contrast Power |
|
|
70 | (1) |
|
|
70 | (2) |
|
Example 5.1: One Factor ANOVA |
|
|
72 | (2) |
|
Example 5.2: One Factor ANOVA with Orthogonal Contrasts |
|
|
74 | (4) |
|
|
78 | (1) |
|
Example 5.3: Two Factor ANOVA with Interactions |
|
|
79 | (4) |
|
Power for Multiple Effects |
|
|
83 | (3) |
|
|
86 | (1) |
|
|
87 | (1) |
6 Within Subjects Designs with ANOVA and Linear Mixed Models |
|
88 | (12) |
|
|
88 | (1) |
|
|
88 | (2) |
|
|
90 | (1) |
|
Example 6.1: One Factor Within Subjects Design |
|
|
91 | (2) |
|
Example 6.2: Sphericity Adjustments |
|
|
93 | (1) |
|
Example 6.3: Linear Mixed Model Approach to Repeated Measures |
|
|
93 | (1) |
|
Example 6.4: A Serious Sphericity Problem |
|
|
94 | (1) |
|
|
94 | (1) |
|
Example 6.5: Trend Analysis |
|
|
95 | (1) |
|
Example 6.6: Two Within Subject Factors Using ANOVA |
|
|
96 | (1) |
|
Example 6.7: Simple Effects Using ANOVA |
|
|
97 | (1) |
|
Example 6.8: Two Factor Within and Simple Effects Using LMM |
|
|
98 | (1) |
|
|
99 | (1) |
|
|
99 | (1) |
7 Mixed Model ANOVA and Multivariate ANOVA |
|
100 | (12) |
|
|
100 | (1) |
|
|
100 | (1) |
|
|
101 | (1) |
|
ANOVA with Between and Within Subject Factors |
|
|
101 | (1) |
|
Example 7.1: ANOVA with One Within Subjects Factor and One Between Subjects Factor |
|
|
101 | (2) |
|
Example 7.2: Linear Mixed Model with One Within Subjects Factor and One Between Subjects Factor |
|
|
103 | (1) |
|
|
104 | (3) |
|
Example 7.3: Multivariate ANOVA |
|
|
107 | (2) |
|
|
109 | (2) |
|
|
111 | (1) |
8 Multiple Regression |
|
112 | (23) |
|
|
112 | (1) |
|
|
112 | (2) |
|
|
114 | (3) |
|
Example 8.1: Power for a Two Predictor Model (R2 Model and Coefficients) |
|
|
117 | (4) |
|
Example 8.2: Power for Three Predictor Models |
|
|
121 | (1) |
|
Example 8.3: Power for Detecting Differences between Two Dependent Coefficients |
|
|
122 | (3) |
|
Example 8.4: Power for Detecting Differences between Two Independent Coefficients |
|
|
125 | (2) |
|
Example 8.5: Comparing Two Independent R2 Values |
|
|
127 | (1) |
|
Multiplicity and Direction of Predictor Correlations |
|
|
128 | (4) |
|
Example 8.6: Power(All) with Three Predictors |
|
|
132 | (1) |
|
|
133 | (1) |
|
|
134 | (1) |
9 Analysis of Covariance, Moderated Regression, Logistic Regression, and Mediation |
|
135 | (22) |
|
|
135 | (1) |
|
|
136 | (3) |
|
Moderated Regression Analysis (Regression with Interactions) |
|
|
139 | (4) |
|
Example 9.2: Regression Analogy (Coefficients) |
|
|
143 | (1) |
|
Example 9.3: Regression Analogy (R2 Change) |
|
|
144 | (1) |
|
Example 9.4: Comparison on Correlations/Simple Slopes |
|
|
145 | (2) |
|
|
147 | (1) |
|
Example 9.5: Logistic Regression with a Single Categorical Predictor |
|
|
148 | (1) |
|
Example 9.6: Logistic Regression with a Single Continuous Predictor |
|
|
149 | (2) |
|
Example 9.7: Power for One Predictor in a Design with Multiple Predictors |
|
|
151 | (1) |
|
Mediation (Indirect Effects) |
|
|
152 | (1) |
|
Example 9.8: One Mediating Variable |
|
|
153 | (1) |
|
Example 9.9: Multiple Mediating Variables |
|
|
154 | (1) |
|
|
155 | (1) |
|
|
156 | (1) |
10 Precision Analysis for Confidence Intervals |
|
157 | (16) |
|
|
158 | (1) |
|
|
158 | (1) |
|
Types of Confidence Intervals |
|
|
159 | (1) |
|
Example 10.1: Confidence Limits around Differences between Means |
|
|
159 | (2) |
|
Determining Levels of Precision |
|
|
161 | (2) |
|
Confidence Intervals around Effect Sizes |
|
|
163 | (1) |
|
Example 10.2: Confidence Limits around d |
|
|
163 | (2) |
|
Precision for a Correlation |
|
|
165 | (1) |
|
Example 10.3: Confidence Limits around r |
|
|
165 | (2) |
|
Example 10.4: Precision for R2 |
|
|
167 | (2) |
|
Supporting Null Hypotheses |
|
|
169 | (1) |
|
Example 10.5: "Supporting" Null Hypotheses |
|
|
169 | (1) |
|
|
170 | (1) |
|
|
171 | (2) |
11 Additional Issues and Resources |
|
173 | (8) |
|
Accessing the Analysis Code |
|
|
173 | (1) |
|
Using Loops to Get Power for a Range of Values |
|
|
173 | (1) |
|
How to Report Power Analyses |
|
|
174 | (1) |
|
Example 11.1: Reporting a Power Analysis for a Chi-Square Analysis |
|
|
175 | (1) |
|
Example 11.2: Reporting a Power Analysis for Repeated Measures ANOVA |
|
|
175 | (1) |
|
Reporting Power if Not Addressed A Priori |
|
|
175 | (1) |
|
Statistical Test Assumptions |
|
|
176 | (1) |
|
Effect Size Conversion Formulae |
|
|
176 | (1) |
|
General (Free) Resources for Power and Related Topics |
|
|
177 | (1) |
|
Resources for Additional Analyses |
|
|
178 | (1) |
|
Improving Power without Increasing Sample Size or Cost |
|
|
179 | (2) |
References |
|
181 | (7) |
Index |
|
188 | |