Preface |
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xix | |
Author Biography |
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xxi | |
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1 Review of Some Basic Statistical Ideas |
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1 | (28) |
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1.1 Introducing Regression Analysis |
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1 | (1) |
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1.2 Classification of Variables |
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2 | (2) |
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1.2.1 Quantitative vs. Qualitative Variables |
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2 | (1) |
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1.2.2 Scale of Measurement Classification |
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2 | (1) |
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1.2.3 Overview of Variable Classification and the Methods to be Presented in this Book |
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3 | (1) |
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1.3 Probability Distributions |
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4 | (1) |
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1.3.1 The Normal Distribution |
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4 | (1) |
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1.4 Statistical Inference |
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5 | (1) |
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6 | (1) |
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1.6 Estimating Population Parameters Using Sample Data |
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7 | (1) |
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1.7 Basic Steps of Hypothesis Testing |
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8 | (3) |
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1.8 Why an Observed p-Value Should Be Interpreted with Caution |
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11 | (1) |
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12 | (1) |
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1.10 Caveats Regarding a Confidence Interval Estimate for an Effect Size |
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13 | (2) |
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1.11 Type I and Type II Errors, Power, and Robustness |
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15 | (1) |
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1.11.1 Type I and Type II errors |
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15 | (1) |
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1.12 Basic Types of Research Studies |
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16 | (3) |
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1.12.1 Observational Studies |
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16 | (1) |
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1.12.2 Controlled Randomized Trials |
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17 | (1) |
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18 | (1) |
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1.13 Why Not Always Conduct a Controlled Randomized Trial? |
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19 | (1) |
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1.14 Importance of Screening for Data Entry Errors |
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19 | (1) |
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1.15 Example 1.1: Environmental Impact Study of a Mine Site |
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19 | (1) |
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1.16 Some SAS Basics: Key Commonalities that Apply to all SAS Programs |
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20 | (2) |
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1.16.1 Temporary and Permanent SAS Data Sets |
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22 | (1) |
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22 | (7) |
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24 | (1) |
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24 | (1) |
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1.A.1 Explanation of SAS Statements in Program 1.1 |
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24 | (2) |
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26 | (1) |
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1.C Listing of Data in the SAS Data File MINESET |
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27 | (2) |
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2 Introduction to Simple Linear Regression |
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29 | (18) |
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2.1 Characteristic Features |
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29 | (1) |
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2.2 Why Use Simple Linear Regression? |
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29 | (1) |
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2.3 Example 2.1: Systolic Blood Pressure and Age |
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30 | (1) |
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2.4 Rationale Underlying a Simple Linear Regression Model |
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30 | (1) |
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2.5 An Equation for the Simple Linear Regression Model |
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31 | (1) |
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2.6 An Alternative Form of the Simple Linear Regression Model |
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32 | (1) |
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2.7 How Simple Linear Regression is Used with Sample Data |
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32 | (2) |
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2.7.1 Properties of Least Squares Estimators |
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34 | (1) |
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2.8 Prediction of a Y Value for an Individual having a Particular X Value |
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34 | (1) |
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2.9 Estimating the Mean Response in the Sampled Population Subgroup Having a Particular X Value |
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35 | (1) |
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2.10 Assessing Accuracy with Prediction Intervals and Confidence Intervals |
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35 | (1) |
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2.11 Ideal Inference Conditions for Simple Linear Regression |
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36 | (2) |
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2.12 Potential Consequences of Violations of Ideal Inference Conditions |
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38 | (1) |
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2.12.1 How Concerned Should We Be About Violations of Ideal Inference Conditions? |
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38 | (1) |
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2.13 What Researchers Need to Know about the Variance of Y Given X |
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39 | (1) |
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2.13.1 An Equation for Mean Square Error, A Model-Dependent Estimator of the Variance of Y given X |
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40 | (1) |
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2.14 Fixed vs. Random X in Simple Linear Regression |
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40 | (1) |
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41 | (6) |
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42 | (1) |
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42 | (1) |
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2.A.1 Explanation of SAS Statements in Program 2.1 |
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43 | (2) |
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2.A.2 A Message in SAS Log for Program 2.1 |
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45 | (2) |
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3 Model Checking in Simple Linear Regression |
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47 | (42) |
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47 | (1) |
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47 | (2) |
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49 | (1) |
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3.4 Residuals as Diagnostic Tools for Model Checking |
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50 | (1) |
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3.5 Obtaining Residuals from the REG Procedure |
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50 | (1) |
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50 | (1) |
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3.5.2 Some Results from the REG Procedure for the Mine Site Example |
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50 | (1) |
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3.6 Raw (Unsealed) Residuals |
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51 | (2) |
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3.6.1 Example of a Raw Residual |
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51 | (1) |
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3.6.2 Estimated Standard Error (Standard Deviation) of a Raw Residual |
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52 | (1) |
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3.6.3 Difficulties Associated with Using Raw Residuals as a Diagnostic Tool |
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52 | (1) |
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3.7 Internally Studentized Residuals |
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53 | (1) |
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3.7.1 Advantages of Internally Studentized Residuals in Evaluating Ideal Inference Conditions |
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54 | (1) |
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3.8 Studentized Deleted Residuals |
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54 | (2) |
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3.8.1 Using a Studentized Deleted Residual to Identify a Regression Outlier |
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55 | (1) |
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55 | (1) |
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3.8.3 Advantages of Studentized Deleted Residuals in Regression Outlier Dectection |
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56 | (1) |
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3.8.4 Caveat Regarding Studentized Deleted Residuals in Outlier Detection |
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56 | (1) |
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3.9 Graphical Evaluation of Ideal Inference Conditions in Simple Linear Regression |
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56 | (8) |
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3.9.1 Graphical Evaluation of Independence of Errors |
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56 | (1) |
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3.9.2 Graphical Evaluation of Linearity and Equality of Variances |
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57 | (2) |
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3.9.3 Graphical Evaluation of Normality |
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59 | (5) |
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3.10 Normality Tests and Gauging the Impact of Non-Normality |
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64 | (1) |
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3.11 Homogeneity of Variance Tests and Gauging the Impact of Unequal Variances in Regression |
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64 | (1) |
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3.12 Screening for Outliers to Detect Possible Recording Errors in Simple Linear Regression |
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65 | (1) |
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3.13 Overview of a Step-by-Step Approach for Checking Ideal Inference Conditions in Simple Linear Regression |
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66 | (2) |
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3.14 Example of Evaluating Ideal Inference Conditions |
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68 | (4) |
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3.15 Checking for Influential Cases |
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72 | (1) |
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3.16 DFBETA: Influence on an Estimated Regression Coefficient |
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73 | (1) |
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3.16.1 General Equation for DFBETA |
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73 | (1) |
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3.16.2 Equation for DFBETA for 8t in Simple Linear Regression |
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73 | (1) |
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3.16.3 Interpretation of DFBETA |
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74 | (1) |
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3.17 DFFITS: Influence of a Case on its Own Predicted Value |
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74 | (1) |
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3.17.1 Equation for DFFITS |
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74 | (1) |
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3.17.2 Interpretation of DFFITS |
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75 | (1) |
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3.18 Cook's Distance: Influence of a Case on All Predicted Values in the Sample |
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75 | (1) |
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3.18.1 Equation for Cook's D |
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75 | (1) |
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3.18.2 Interpretation of Cook's Distance |
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76 | (1) |
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3.19 Caveats Regarding Cut-Off Values for Measures of Influence |
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76 | (1) |
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3.20 Detecting Multiple Influential Cases That Occur in a Cluster |
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76 | (1) |
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3.21 Checking for Potentially Influential Cases in Example 1.1 |
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77 | (2) |
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3.21.1 DFBETAS Results for Example 1.1 |
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77 | (1) |
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3.21.2 DFFITS Results for Example 1.1 |
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78 | (1) |
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3.21.3 Cook's D Results for Example 1.1 |
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79 | (1) |
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3.22 Discussion and Conclusion Regarding Influence in Example 1.1 |
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79 | (1) |
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3.23 Summary of Model Checking for Example 1.1 |
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80 | (1) |
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80 | (9) |
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82 | (1) |
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82 | (1) |
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3.A.1 Explanation of SAS Statements in Program 3.1A Not Encountered in Previous Programs |
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82 | (1) |
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83 | (1) |
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3.B.1 Explanation of SAS statements in Program 3.1B |
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84 | (1) |
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85 | (2) |
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3.C.1 Explanation of Program 3.1C |
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87 | (2) |
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4 Interpreting a Simple Linear Regression Analysis |
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89 | (16) |
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89 | (1) |
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4.2 A Basic Question to Ask in Simple Linear Regression |
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89 | (1) |
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90 | (1) |
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4.3.1 The Test Statistic for the Model F-Test |
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90 | (1) |
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90 | (1) |
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4.4 The t-Test of β1 = 0 vs. β1 ≠ 0 in the Sampled Population |
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91 | (1) |
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92 | (1) |
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4.5 Possible Interpretations of a Large p-Value from a Model F-Test or Equivalent t-Test of β1 vs. β1 ≠ in Simple Linear Regression |
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92 | (1) |
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4.6 Possible Interpretations of a Small p-Value from a Model F-Test or Equivalent t-test of β1 = 0 vs. β1 ≠ in Simple Linear Regression |
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93 | (1) |
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4.7 Evaluating the Extent of the Usefulness of X for Explaining Y in a Simple Linear Regression Model |
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94 | (1) |
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4.8 A Confidence Interval Estimate for β1, the Regression Coefficient for X in Simple Linear Regression |
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94 | (2) |
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4.8.1 Interpreting a 95% Confidence Interval Estimate for β1 |
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95 | (1) |
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95 | (1) |
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4.9 R2, the Coefficient of Determination |
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96 | (1) |
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96 | (1) |
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4.9.2 Some Issues Interpreting R2 |
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97 | (1) |
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97 | (1) |
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4.10 Root Mean Square Error |
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97 | (1) |
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4.11 Coefficient of Variation for the Model |
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98 | (1) |
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4.12 Estimating a Confidence Interval for the Subpopulation Mean of Y Given a Specified X Value |
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98 | (1) |
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98 | (1) |
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4.12.2 Equation for Estimating the Endpoints of a 95% Conventional Confidence Interval for the Mean of Y for a Given X Value |
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99 | (1) |
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4.13 Estimating a Prediction Interval for an Individual Value of Y at a Particular X Value |
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99 | (2) |
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100 | (1) |
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4.13.2 Equation for Estimating the Endpoints of a 95% Conventional Prediction Interval for an Individual Y Given X |
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100 | (1) |
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101 | (1) |
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102 | (3) |
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103 | (1) |
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103 | (2) |
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5 Introduction to Multiple Linear Regression |
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105 | (12) |
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5.1 Characteristic Features of a Multiple Linear Regression Model |
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105 | (1) |
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5.2 Why Use a Multiple Linear Regression Model? |
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105 | (1) |
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106 | (1) |
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5.4 Equation for a First Order Multiple Linear Regression Model |
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107 | (1) |
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5.5 Alternate Equation for a First Order Multiple Linear Regression Model |
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107 | (1) |
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5.6 How Multiple Linear Regression is Used with Sample Data |
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107 | (2) |
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5.7 Estimation of a Y Value for an Individual from the Sampled Population |
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109 | (1) |
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5.7.1 Equation for Estimating a Y Value for an Individual from the Sampled Population |
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109 | (1) |
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109 | (1) |
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5.8 Using Multiple Linear Regression to Estimate the Mean Y Value in a Population Subgroup with Particular Values for the Explanatory Variables |
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110 | (1) |
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5.9 Assessing Accuracy of Predicted Values |
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110 | (1) |
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5.10 Ideal Inference Conditions for a Multiple Linear Regression Model |
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110 | (1) |
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5.11 Measurement Error in Explanatory Variables in Multiple Linear Regression |
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111 | (1) |
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5.12 Collinearity -- Why Worry? |
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112 | (1) |
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5.13 Why the Estimation of Variance of Y Given the X Variables is Critical in Multiple Linear Regression |
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113 | (1) |
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114 | (3) |
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115 | (1) |
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115 | (1) |
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5.B Example 5.1 Data Values |
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116 | (1) |
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6 Before Interpreting a Multiple Linear Regression Analysis |
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117 | (20) |
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117 | (1) |
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6.2 Evaluating Collinearity |
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117 | (3) |
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6.2.1 A Method for Diagnosing Collinearity |
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118 | (1) |
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6.2.2 Interpreting Collinearity Diagnostics from the Method Proposed by Belsley (1991) |
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118 | (1) |
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6.2.3 Variance Inflation Factor: Another Measure of Collinearity |
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119 | (1) |
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6.2.4 Further Comments Regarding Collinearity Diagnosis |
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120 | (1) |
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6.3 A Ten-Step Approach for Checking Ideal Inference Conditions in Multiple Linear Regression |
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120 | (3) |
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6.4 Example -- Evaluating Ideal Inference Conditions |
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123 | (4) |
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6.5 Identifying Influential Cases |
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127 | (1) |
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6.6 Summary of Results Regarding Potentially Influential Cases based on Cook's D, DFBETAS, and DFFITS Values Output from Program 6.1C |
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128 | (3) |
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129 | (1) |
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129 | (2) |
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6.6.3 Potentially Influential Cases |
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131 | (1) |
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131 | (6) |
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133 | (1) |
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133 | (1) |
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134 | (1) |
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135 | (2) |
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7 Interpreting an Additive Multiple Linear Regression Model |
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137 | (20) |
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137 | (1) |
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7.2 Height at Age 18 Example |
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137 | (1) |
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138 | (2) |
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7.3.1 Model F-Test and Some Other Results Generated by the Model Statement of the REG Procedure for the Height at Age 18 Example |
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138 | (1) |
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7.3.2 Interpretation When the Model F-Test Statistic for a Multiple Linear Regression Model Has a Small p-Value |
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139 | (1) |
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7.3.3 Possible Interpretations When the Model F-Test Statistic for an Additive Multiple Linear Regression Model Has a Large p-Value |
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140 | (1) |
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7.4 R2 in Multiple Linear Regression |
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140 | (1) |
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140 | (1) |
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7.4.2 Issues Regarding R2 |
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141 | (1) |
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141 | (1) |
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141 | (1) |
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7.5.1 Equation for Adjusted R2 |
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141 | (1) |
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7.5.2 Issues Regarding Adjusted R2 |
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142 | (1) |
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142 | (1) |
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142 | (1) |
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7.7 Coefficient of Variation for the Model |
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142 | (1) |
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7.8 Partial t-Tests in a Multiple Linear Regression Model |
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143 | (2) |
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7.8.1 Equation of the Test Statistic for a Partial t-Test of a Regression Coefficient |
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143 | (1) |
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7.8.2 Partial t-Test Examples |
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144 | (1) |
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7.9 Partial t-Tests and the Issue of Multiple Testing |
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145 | (1) |
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7.10 The Model F-Test, Partial t-Tests, and Collinearity |
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145 | (1) |
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7.11 Why Estimate a Confidence Interval for Bp |
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145 | (2) |
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146 | (1) |
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7.11.2 Equation for a Conventional Confidence Interval Estimate for Bj |
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146 | (1) |
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7.12 Estimating a Conventional Confidence Interval for the Mean Y Value in a Population Subgroup with a Particular Combination of the Predictor Variables |
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147 | (1) |
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147 | (1) |
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7.13 Estimating a Prediction Interval for an Individual Y Value Given Specified Values for the Predictor Variables |
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148 | (1) |
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7.14 Further Evaluation of Influence in the Height at Age 18 Example |
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149 | (1) |
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7.15 Extrapolation in Multiple Regression |
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150 | (3) |
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7.15.1 Delivery Time Data Example |
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151 | (1) |
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7.15.2 Cases Sorted by Hat Values from Program 7.2 |
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151 | (2) |
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153 | (4) |
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154 | (1) |
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154 | (1) |
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154 | (1) |
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7.B.1 Explanation of Program 7.2 |
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155 | (2) |
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8 Modelling a Two-Way Interaction Between Continuous Predictors in Multiple Linear Regression |
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157 | (24) |
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8.1 Introduction to a Two-Way Interaction |
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157 | (1) |
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8.2 A Two-Way Interaction Model in Multiple Linear Regression |
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158 | (2) |
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8.3 Investigating a Two-Way Interaction Using Sample Data |
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160 | (1) |
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8.4 Example 8.1: Physical Endurance as a Linear Function of Age, Exercise, and their Interaction |
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161 | (1) |
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8.5 Facilitating Interpretation in Two-Way Interaction Regression via Centring |
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161 | (2) |
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8.5.1 Example of Centring to Facilitate Interpretation |
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163 | (1) |
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8.6 A Suggested Approach for Applying a Multiple Linear Regression Two-Way Interaction Model with Two Continuous Predictors |
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163 | (2) |
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8.7 An Example Using the Suggested Approach for Applying an Interaction Model with Two Continuous Predictors |
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165 | (1) |
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8.8 Results from Application of a Multiple Regression Interaction Analysis with Centred AGE and Uncentered EXER in the Physical Endurance Example |
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166 | (1) |
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8.9 Interpretation of Regression Coefficient Estimates for the Interaction Model Fitted to Example 8.1 |
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167 | (1) |
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8.10 Visualization of the Interaction Effect Observed in Example 8.1 |
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168 | (2) |
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8.11 Predicting Endurance on a Treadmill |
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170 | (1) |
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171 | (10) |
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173 | (1) |
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8.A Summary of Evaluation of Ideal Inference Conditions for the Physical Endurance Example with a Two-Way Interaction Model |
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173 | (3) |
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8.B Summary of Influence Diagnostics for the Physical Endurance Example with a Two-Way Interaction Model |
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176 | (1) |
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177 | (1) |
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178 | (2) |
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8.D.1 Explanation of SAS Statements in Program 8.2 |
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180 | (1) |
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9 Evaluating a Two-Way Interaction Between a Qualitative and a Continuous Predictor in Multiple Linear Regression |
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181 | (20) |
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181 | (1) |
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9.2 How to Include a Qualitative Variable in a Multiple Linear Regression Model |
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181 | (1) |
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9.3 Full Rank Reference Cell Coding |
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182 | (1) |
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9.4 Example 9.1: Mussel Weight |
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182 | (1) |
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9.5 Example Using a Nine-Step Approach for Applying a Multiple Linear Regression with a Two-Way Interaction between a Continuous and Qualitative Predictor |
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183 | (1) |
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9.6 Evaluating Influence in Multiple Regression Models which Involve Qualitative Variables |
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184 | (1) |
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9.7 Summary of Influence Evaluation in the Multiple Regression Interaction Analysis for the Mussel Example |
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185 | (1) |
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9.8 Results from Program 9.2: Two-Way Interaction Regression Analysis between a Qualitative Predictor (Reference Cell Coding) and a Centred Continuous Predictor |
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186 | (1) |
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9.9 Interpreting Results of the Model F-Test and Parameter Estimates Reported in Section 9.8 |
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187 | (4) |
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187 | (1) |
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9.9.2 Interpretation of Model F-Test |
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187 | (1) |
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9.9.3 Interpretation of the Estimated Regression Coefficient for AGECILOC |
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187 | (2) |
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9.9.4 Interpretation of the Estimated Regression Coefficient for AGEC |
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189 | (1) |
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9.9.5 Interpretation of the Estimated Regression Coefficient for ILOC |
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189 | (1) |
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9.9.6 Interpretation of the Sample Model Intercept |
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190 | (1) |
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191 | (10) |
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192 | (1) |
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9.A Evaluation of Ideal Inference Conditions for the Mussel Example |
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192 | (2) |
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9.B Program 9.1: Getting to Know the Mussel Data |
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194 | (1) |
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9.B.1 Explanation of Statements in Program 9.1 |
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195 | (1) |
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9.C Program 9.2: Two-Way Interaction Regression Analysis between a Qualitative Predictor (Reference Cell Coding) and a Centred Continuous Predictor |
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196 | (2) |
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9.C.1 Explanation of Selected SAS Statements in Program 9.2 |
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198 | (1) |
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199 | (2) |
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10 Subset Selection of Predictor Variables in Multiple Linear Regression |
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201 | (26) |
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201 | (1) |
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10.2 Under-Fitting, Over-Fitting, and the Bias-Variance Trade-Off |
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202 | (1) |
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10.3 Overview of Traditional Model Selection Algorithms |
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202 | (2) |
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202 | (1) |
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10.3.2 Backward Elimination |
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203 | (1) |
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10.3.3 Stepwise Selection |
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203 | (1) |
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10.3.4 All Subsets Selection Algorithm |
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203 | (1) |
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10.3.5 The Impact of Collinearity on Traditional Sequential Selection Algorithms |
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203 | (1) |
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10.4 Fit Criteria Used in Model Selection Methods |
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204 | (4) |
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204 | (1) |
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10.4.2 Akaike's Information Criterion |
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205 | (1) |
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10.4.3 The Corrected Akaike's Information Criterion |
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205 | (1) |
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10.4.4 Average Square Error |
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206 | (1) |
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10.4.5 Mallows' Cp Statistic |
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206 | (1) |
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206 | (1) |
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10.4.7 The PRESS Statistic |
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207 | (1) |
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10.4.8 Schwarz's Bayesian Information Criterion |
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207 | (1) |
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10.4.9 Significance Level (p-Value) Criterion |
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207 | (1) |
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10.5 Post-Selection Inference Issues |
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208 | (1) |
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10.6 Predicting Percentage Body Fat: Naval Academy Example |
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208 | (3) |
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10.7 Model Selection and the REG Procedure |
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211 | (2) |
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10.8 Model Selection and the GLMSELECT Procedure |
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213 | (8) |
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10.8.1 Example of Subset Selection in GLMSELECT |
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214 | (1) |
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10.8.2 Model Information: Program 10.2 |
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214 | (1) |
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10.8.3 Model Building Summary Results: Program 10.2 |
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215 | (1) |
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10.8.4 Comments Regarding Model Building Summary Results |
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216 | (1) |
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10.8.5 Selected Model Results: Program 10.2 |
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217 | (1) |
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10.8.6 Comments Regarding Standard Errors of the Partial Regression Coefficients for the Selected Model |
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218 | (1) |
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10.8.7 Average Square Error Plot: Program 10.2 |
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218 | (1) |
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10.8.8 Criteria Panel Plot: Program 10.2 |
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218 | (3) |
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10.9 Other Features Available in GLMSELECT |
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221 | (1) |
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221 | (6) |
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223 | (1) |
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223 | (2) |
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225 | (2) |
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11 Evaluating Equality of Group Means with a One-Way Analysis of Variance |
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227 | (26) |
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11.1 Characteristic Features of a One-Way Analysis of Variance Model |
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227 | (1) |
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11.2 Fixed Effects vs. Random Effects in One-Way ANOVA |
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227 | (2) |
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11.3 Why Use a One-Way Fixed Effects Analysis of Variance? |
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229 | (1) |
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229 | (1) |
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11.5 The Means Model for a One-Way Fixed Effects ANOVA |
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230 | (1) |
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11.6 Basic Concepts Underlying a One-Way Fixed Effects ANOVA |
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230 | (2) |
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11.7 Ideal Inference Conditions for One-Way Fixed Effects ANOVA |
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232 | (1) |
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11.8 Potential Consequences of Violating Ideal Inference Conditions for One-Way Fixed Effects ANOVA Test of Equality of Group Means |
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232 | (2) |
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11.9 Overview of General Approaches for Evaluating Ideal Inference Conditions for a One-Way Fixed Effects ANOVA |
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234 | (1) |
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11.10 Suggestions for Alternative Approaches When Ideal Inference Conditions are Not Reasonable |
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234 | (1) |
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11.11 Testing Equality of Group Variances |
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235 | (1) |
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11.12 Some Earlier Tests for Equality of Variances |
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235 | (1) |
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235 | (1) |
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11.12.2 Hartley's Fmax Test |
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236 | (1) |
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11.13 ANOVA-Based Tests for Equality of Variances |
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236 | (2) |
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11.13.1 Levene's Approach for Testing Equality of Variances |
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236 | (1) |
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11.13.2 Brown's and Forsythe's Tests of Variances |
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237 | (1) |
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237 | (1) |
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11.14 Simulation Studies on ANOVA-Based Equality of Variances Tests |
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238 | (1) |
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11.15 Additional Comments about ANOVA-Based Equality of Variances Tests |
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239 | (1) |
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11.16 Overview of a Step-by-Step Approach for Checking Ideal Inference Conditions |
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239 | (1) |
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11.17 Nine-Step Approach for Evaluating Ideal Inference Conditions: Task Study Example |
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240 | (3) |
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11.18 One-Way ANOVA Model F-Test of Means |
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243 | (2) |
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11.18.1 Task Study Example |
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243 | (1) |
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11.18.2 What is a Linear Contrast? |
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244 | (1) |
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11.18.3 Comments on Model F-Test in One-Way Fixed Effects ANOVA |
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244 | (1) |
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11.19 Testing Equality of Population Means When Population Variances Are Unequal |
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245 | (1) |
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245 | (1) |
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11.19.2 Fitting Unequal Variance ANOVA Models |
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246 | (1) |
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11.19.3 Other Suggestions |
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246 | (1) |
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246 | (7) |
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248 | (1) |
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11.A Program 11.1: Data Screening |
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248 | (1) |
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249 | (1) |
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11.C Explanation of Statements in Program 11.2 |
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250 | (3) |
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12 Multiple Testing and Simultaneous Confidence Intervals |
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253 | (34) |
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12.1 Multiple Testing and the Multiplicity Problem |
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253 | (1) |
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12.2 Measures of Error Rates |
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253 | (1) |
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12.3 Overview of Multiple Testing Procedures |
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254 | (2) |
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12.4 The Least Significant Difference: A Multiplicity-Unadjusted Procedure |
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256 | (2) |
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256 | (1) |
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12.4.2 Ideal Inference Conditions |
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256 | (1) |
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257 | (1) |
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12.4.4 SAS and the LSD Procedure |
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257 | (1) |
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12.5 Examples of Familywise Error Rate Controlling Procedures |
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258 | (1) |
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12.6 The Bonferroni Method |
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259 | (3) |
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259 | (1) |
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12.6.2 Example 12.1: An Application of the Bonferroni Method |
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260 | (1) |
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12.6.3 Why the Bonferroni Method Can Be Conservative |
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261 | (1) |
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12.6.4 The Bonferroni Method and All Possible Pairwise Comparisons of Group Means |
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261 | (1) |
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12.7 The Tukey-Kramer Method for All Pairwise Comparisons |
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262 | (2) |
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262 | (1) |
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12.7.2 SAS and the Tukey-Kramer Method |
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263 | (1) |
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12.8 A Simulation-Based Method for All Pairwise Comparisons |
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264 | (1) |
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264 | (1) |
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12.8.2 SAS and Simulation-Based Adjusted p-Value Estimates |
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264 | (1) |
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12.8.3 Task Study Example of Simulation-Based Adjusted p-Values Estimates |
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265 | (1) |
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12.9 Dunnett's Method for "Treatment" vs. "Control" Comparisons |
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265 | (2) |
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265 | (1) |
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12.9.2 SAS and Dunnett's Test |
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266 | (1) |
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12.10 Scheffe's Method for "Data Snooping" |
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267 | (2) |
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267 | (1) |
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12.10.2 Application of Scheffe's Method |
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268 | (1) |
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12.10.3 SAS and Scheffe's method |
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268 | (1) |
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12.11 Ordinary Confidence Intervals and the Multiplicity Issue |
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269 | (1) |
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269 | (1) |
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12.11.2 Why Does the Overall Confidence Level Decrease as the Number of Ordinary Confidence Intervals Increases? |
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269 | (1) |
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12.12 Controlling Familywise Error Rate for Confidence Intervals |
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270 | (3) |
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270 | (1) |
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12.12.2 Task Study Example |
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271 | (1) |
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12.12.3 SAS and Controlling Familywise Error Rate for Confidence Intervals |
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272 | (1) |
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12.13 Confidence Bands for Simple Linear Regression |
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273 | (5) |
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12.13.1 The Working-Hotelling Method |
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274 | (1) |
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12.13.2 SAS and Working-Hotelling's Confidence Band |
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274 | (1) |
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12.13.3 A Discrete Simulation-Based Method |
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275 | (3) |
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12.14 Single Step vs. Sequential Multiplicity-Adjusted Procedures |
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278 | (1) |
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12.15 The Holm-Bonferroni Sequential Procedure |
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278 | (3) |
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278 | (1) |
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12.15.2 How to Compute Holm-Bonferroni Multiplicity-Adjusted p-Values |
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279 | (1) |
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12.15.3 SAS and the Holm-Bonferroni Method |
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280 | (1) |
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12.15.4 Familywise Adjusted p-Values for Partial t-Tests from Program 12.2 |
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281 | (1) |
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12.16 Adjusting for Multiplicity Using Resampling Methods |
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281 | (1) |
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12.17 Benjamini-Hochberg's False Discovery Rate Method |
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281 | (3) |
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281 | (1) |
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12.17.2 Benjamini-Hochberg's Adjusted p-Values |
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282 | (1) |
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12.17.3 SAS and Benjamini-Hochberg's FDR-Controlling Method |
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283 | (1) |
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12.17.4 Interpreting Results from a FDR-Controlling Procedure |
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284 | (1) |
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12.18 Recent Advances in FDR-Controlling Procedures |
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284 | (1) |
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285 | (2) |
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13 Analysis of Covariance: Adjusting Group Means for Nuisance Variables Using Regression |
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287 | (64) |
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287 | (1) |
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13.2 Characteristic Features of a One-Way Analysis of Covariance Linear Model |
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287 | (1) |
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13.3 Why Apply an Analysis of Covariance? |
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288 | (1) |
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13.4 Example 13.1: Exercise Programs and Heart Rate |
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288 | (1) |
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13.5 General Equation for a One-Way Analysis of Covariance with a Single Continuous Covariate |
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289 | (1) |
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13.6 Two Critical Decisions in an Analysis of Covariance |
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290 | (4) |
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13.7 Implementing a One-Way ANCOVA A Step-by-Step Approach |
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294 | (3) |
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13.8 An Example of Implementing an Analysis of Covariance |
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297 | (11) |
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13.9 What If an Equal Slopes Analysis Had Been Applied to the Exercise Program Data? |
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308 | (2) |
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309 | (1) |
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13.10 What If a One-Way ANOVA Had Been Applied to the Exercise Program Data? |
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310 | (2) |
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13.11 Example 13.2: Effect of Study Methods on Exam Scores Adjusted for Pretest Scores |
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312 | (1) |
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13.12 A Step-by-Step Analysis of Covariance for Example 13.2 |
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312 | (9) |
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13.13 References for Other Approaches for Covariate Adjustment |
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321 | (1) |
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321 | (30) |
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323 | (1) |
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13.A Details of a Nine-Step Evaluation of Ideal Inference Conditions for Simple Linear Regressions in Exercise Programs A and B in Example 13.1 |
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323 | (6) |
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13.B Details of Evaluation of Ideal Inference Conditions for Simple Linear Regressions of Postscore vs. Prescore in Example 13.2 |
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329 | (6) |
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335 | (1) |
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336 | (2) |
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338 | (1) |
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339 | (1) |
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340 | (2) |
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342 | (1) |
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343 | (1) |
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344 | (1) |
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13.K Summary of SAS Programs for Example 13.2 |
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345 | (1) |
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345 | (1) |
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346 | (2) |
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348 | (1) |
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349 | (1) |
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349 | (1) |
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350 | (1) |
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14 Alternative Approaches If Ideal Inference Conditions Are Not Satisfied |
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351 | (38) |
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351 | (1) |
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14.2 When Random Sampling Is Not an Option |
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351 | (1) |
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14.3 When Errors Are Not All Independent |
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352 | (2) |
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352 | (1) |
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14.3.2 Fitting a Model for Correlated Data |
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353 | (1) |
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354 | (5) |
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14.4.1 Advantages and Disadvantages of a Data Transformation Approach |
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354 | (1) |
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14.4.2 Power Transformations |
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355 | (1) |
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14.4.3 Applying Power Transformations in SAS |
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356 | (1) |
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14.4.4 Log Transformations |
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357 | (2) |
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14.5 Alternative Approaches When Linearity Is Not Satisfied |
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359 | (8) |
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359 | (1) |
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14.5.2 Adding One or More Predictor Variable(s) to the Model to Achieve Linearity |
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359 | (1) |
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14.5.3 Transformations and the Linearity Assumption |
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359 | (5) |
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14.5.4 Overview of Rank Regression |
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364 | (1) |
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14.5.5 Polynomial Regression and Nonlinearity |
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365 | (2) |
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14.5.6 Overview of Fitting a Nonlinear Model |
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|
367 | (1) |
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14.6 Alternative Approaches When Variances Are Not All Equal |
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367 | (3) |
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367 | (1) |
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14.6.2 Transforming Data to Achieve Equality of Variances |
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368 | (1) |
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14.6.3 Overview of Weighted Least Squares for Unequal Variances |
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369 | (1) |
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14.7 Alternative Approaches If Model Errors Are Not Normal |
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370 | (1) |
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370 | (1) |
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14.7.2 Reducing Skewness with Power Transformations |
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370 | (1) |
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371 | (1) |
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371 | (2) |
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372 | (1) |
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14.9.2 The Bootstrap Estimate of Standard Error |
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372 | (1) |
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14.9.3 The Bootstrap Percentile Confidence Interval |
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373 | (1) |
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14.10 When Is n Too Small And What Is An Adequate Number Of Bootstrap Samples? |
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373 | (4) |
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14.10.1 Example of a Bootstrapping Application |
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374 | (3) |
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14.11 Alternative Approaches If Harmful Collinearity Is Detected |
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377 | (1) |
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378 | (11) |
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380 | (1) |
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380 | (1) |
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380 | (2) |
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382 | (1) |
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383 | (1) |
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384 | (1) |
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14.E.1 Explanation of SAS Statements in Program 14.E |
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|
385 | (4) |
References |
|
389 | (12) |
Index |
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401 | |