Preface |
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xi | |
1 Introduction |
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1 | (6) |
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1.1 Uses of Statistics in Medicine and Epidemiology |
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1 | (1) |
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1.2 Structure and Objectives of This Book |
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2 | (3) |
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1.3 Nomenclature in This Book |
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5 | (1) |
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5 | (2) |
2 Vector Geometry of Linear Models for Epidemiologists |
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7 | (10) |
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7 | (1) |
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2.2 Basic Concepts of Vector Geometry in Statistics |
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7 | (2) |
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2.3 Correlation and Simple Regression in Vector Geometry |
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9 | (2) |
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2.4 Linear Multiple Regression in Vector Geometry |
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11 | (1) |
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2.5 Significance Testing of Correlation and Simple Regression in Vector Geometry |
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12 | (2) |
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2.6 Significance Testing of Multiple Regression in Vector Geometry |
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14 | (1) |
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15 | (2) |
3 Path Diagrams and Directed Acyclic Graphs |
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17 | (10) |
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17 | (1) |
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17 | (4) |
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3.1.1 The Path Diagram for Simple Linear Regression |
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18 | (2) |
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3.1.1.1 Regression Weights, Path Coefficients and Factor Loadings |
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19 | (1) |
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3.1.1.2 Exogenous and Endogenous Variables |
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19 | (1) |
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3.1.2 The Path Diagram for Multiple Linear Regression |
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20 | (1) |
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3.2 Directed Acyclic Graphs |
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21 | (4) |
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3.2.1 Identification of Confounders |
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22 | (1) |
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3.2.2 Backdoor Paths and Colliders |
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23 | (1) |
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3.2.3 Example of a Complex DAG |
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24 | (1) |
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3.3 Direct and Indirect Effects |
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25 | (1) |
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26 | (1) |
4 Mathematical Coupling and Regression to the Mean in the Relation between Change and Initial Value |
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27 | (24) |
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27 | (2) |
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4.2 Historical Background |
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29 | (1) |
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4.3 Why Should Change Not Be Regressed on Initial Value? A Review of the Problem |
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29 | (1) |
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4.4 Proposed Solutions in the Literature |
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30 | (7) |
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4.4.1 Blomqvist's Formula |
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30 | (1) |
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4.4.2 Oldham's Method: Testing Change and Average |
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30 | (2) |
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4.4.3 Geometrical Presentation of Oldham's Method |
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32 | (1) |
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4.4.4 Variance Ratio Test |
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32 | (2) |
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4.4.5 Structural Regression |
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34 | (1) |
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4.4.6 Multilevel Modelling |
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35 | (1) |
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4.4.7 Latent Growth Curve Modelling |
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36 | (1) |
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4.5 Comparison between Oldham's Method and Blomqvist's Formula |
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37 | (1) |
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4.6 Oldham's Method and Blomqvist's Formula Answer Two Different Questions |
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38 | (1) |
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4.7 What Is Galton's Regression to the Mean? |
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39 | (1) |
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4.8 Testing the Correct Null Hypothesis |
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40 | (5) |
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4.8.1 The Distribution of the Correlation Coefficient between Change and Initial Value |
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41 | (2) |
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4.8.2 Null Hypothesis for the Baseline Effect on Treatment |
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43 | (1) |
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4.8.3 Fisher's Z-Transformation |
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43 | (1) |
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4.8.4 A Numerical Example |
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44 | (1) |
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4.8.5 Comparison with Alternative Methods |
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44 | (1) |
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4.9 Evaluation of the Categorisation Approach |
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45 | (2) |
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4.10 Testing the Relation between Changes and Initial Values When There Are More than Two Occasions |
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47 | (1) |
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48 | (3) |
5 Analysis of Change in Pre-/Post-Test Studies |
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51 | (22) |
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51 | (1) |
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5.2 Analysis of Change in Randomised Controlled Trials |
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51 | (2) |
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5.3 Comparison of Six Methods |
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53 | (7) |
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54 | (1) |
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5.3.1.1 Test the Post-Treatment Scores Only |
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54 | (1) |
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5.3.1.2 Test the Change Scores |
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54 | (1) |
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5.3.1.3 Test the Percentage Change Scores |
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54 | (1) |
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5.3.1.4 Analysis of Covariance |
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54 | (1) |
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5.3.2 Multivariate Statistical Methods |
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55 | (4) |
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5.3.2.1 Random Effects Model |
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55 | (1) |
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5.3.2.2 Multivariate Analysis of Variance |
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56 | (3) |
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59 | (1) |
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5.6 Analysis of Change in Non-Experimental Studies: Lord's Paradox |
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60 | (5) |
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5.6.1 Controversy around Lord's Paradox |
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62 | (2) |
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5.6.1.1 Imprecise Statement of Null Hypothesis |
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62 | (1) |
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5.6.1.2 Causal Inference in Non-Experimental Study Design |
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63 | (1) |
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5.6.2 Variable Geometry of Lord's Paradox |
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64 | (1) |
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5.6.3 Illustration of the Difference between ANCOVA and Change Scores in RCTs Using Variable Space Geometry |
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65 | (1) |
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5.7 ANCOVA and t-Test for Change Scores Have Different Assumptions |
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65 | (6) |
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5.7.1 Scenario One: Analysis of Change for Randomised Controlled Trials |
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67 | (2) |
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5.7.2 Scenario Two: The Analysis of Change for Observational Studies |
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69 | (2) |
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71 | (2) |
6 Collinearity and Multicollinearity |
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73 | (24) |
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6.1 Introduction: Problems of Collinearity in Linear Regression |
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73 | (3) |
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76 | (1) |
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77 | (2) |
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6.4 Mathematical Coupling and Collinearity |
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79 | (1) |
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6.5 Vector Geometry of Collinearity |
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79 | (5) |
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6.5.1 Reversed Relation between the Outcome and Covariate due to Collinearity |
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80 | (1) |
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6.5.2 Unstable Regression Models due to Collinearity |
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81 | (1) |
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6.5.3 The Relation between the OutcomeExplanatory Variable's Correlations and Collinearity |
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82 | (2) |
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6.6 Geometrical Illustration of Principal Components Analysis as a Solution to Multicollinearity |
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84 | (1) |
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6.7 Example: Mineral Loss in Patients Receiving Parenteral Nutrition |
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85 | (4) |
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6.8 Solutions to Collinearity |
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89 | (5) |
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6.8.1 Removal of Redundant Explanatory Variables |
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89 | (1) |
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89 | (1) |
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6.8.3 Principal Component Analysis |
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90 | (3) |
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93 | (1) |
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94 | (3) |
7 Is 'Reversal Paradox' a Paradox? |
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97 | (22) |
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7.1 A Plethora of Paradoxes: The Reversal Paradox |
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97 | (1) |
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7.2 Background: The Foetal Origins of Adult Disease Hypothesis (Barker's Hypothesis) |
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98 | (11) |
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7.2.1 Epidemiological Evidence on the Foetal Origins Hypothesis |
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99 | (1) |
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7.2.2 Criticisms of the Foetal Origins Hypothesis |
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100 | (2) |
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7.2.3 Reversal Paradox and Suppression in Epidemiological Studies on the Foetal Origins Hypothesis |
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102 | (2) |
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7.2.4 Catch-Up Growth and the Foetal Origins Hypothesis |
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104 | (3) |
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7.2.5 Residual Current Body Weight: A Proposed Alternative Approach |
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107 | (1) |
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108 | (1) |
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7.3 Vector Geometry of the Foetal Origins Hypothesis |
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109 | (2) |
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7.4 Reversal Paradox and Adjustment for Current Body Size: Empirical Evidence from Meta-Analysis |
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111 | (1) |
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112 | (5) |
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7.5.1 The Reversal Paradox and the Foetal Origins Hypothesis |
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112 | (3) |
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7.5.2 Multiple Adjustments for Current Body Sizes |
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115 | (1) |
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7.5.3 Catch-Up Growth and the Foetal Origins Hypothesis |
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116 | (1) |
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117 | (2) |
8 Testing Statistical Interaction |
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119 | (20) |
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8.1 Introduction: Testing Interactions in Epidemiological Research |
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119 | (2) |
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8.1 Testing Statistical Interaction between Categorical Variables |
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121 | (3) |
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8.2 Testing Statistical Interaction between Continuous Variables |
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124 | (4) |
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8.3 Partial Regression Coefficient for Product Term in Regression Models |
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128 | (2) |
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8.4 Categorization of Continuous Explanatory Variables |
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130 | (1) |
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8.5 The Four-Model Principle in the Foetal Origins Hypothesis |
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131 | (1) |
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8.6 Categorization of Continuous Covariates and Testing Interaction |
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132 | (2) |
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132 | (1) |
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133 | (1) |
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134 | (3) |
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137 | (2) |
9 Finding Growth Trajectories in Lifecourse Research |
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139 | (26) |
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139 | (7) |
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9.1.1 Example: Catch-Up Growth and Impaired Glucose Tolerance |
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140 | (1) |
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9.1.2 Galton and Regression to the Mean |
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141 | (3) |
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9.1.3 Revisiting the Growth Trajectory of Men with Impaired Glucose Tolerance |
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144 | (2) |
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9.2 Current Approaches to Identifying Postnatal Growth Trajectories in Lifecourse Research |
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146 | (16) |
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9.2.1 The Lifecourse Plot |
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147 | (3) |
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9.2.2 Regression with Changes Scores |
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150 | (1) |
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9.2.3 Latent Growth Curve Models |
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151 | (8) |
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9.2.4 Growth Mixture Models |
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159 | (3) |
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162 | (3) |
10 Partial Least Squares Regression for Lifecourse Research |
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165 | (22) |
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165 | (1) |
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166 | (1) |
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166 | (1) |
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167 | (15) |
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167 | (3) |
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170 | (1) |
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171 | (1) |
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10.4.4 PLS and Perfect Collinearity |
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172 | (1) |
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10.4.5 Singular Value Decomposition, PCA and PLS Regression |
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173 | (3) |
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10.4.6 Selection of PLS Component |
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176 | (1) |
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10.4.7 PLS Regression for Lifecourse Data Using Weight z-Scores at Birth, Changes in z-Scores, and Current Weight z-Scores |
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177 | (1) |
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10.4.8 The Relationship between OLS Regression and PLS Regression Coefficients |
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178 | (3) |
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10.4.9 PLS Regression for Lifecourse Data Using Weight z-Scores Measured at Six Different Ages |
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181 | (1) |
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10.4.10 PLS Regression for Lifecourse Data Using Weight z-Scores Measured at Six Different Ages and Five Changes in z-Scores |
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182 | (1) |
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182 | (2) |
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184 | (3) |
11 Concluding Remarks |
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187 | (2) |
References |
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189 | (14) |
Index |
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203 | |