SAS for Mixed Models

Chapter 4: Power, Precision, and Sample Size I: Basic Concepts

4.1 Introduction. 101

4.2 Understanding Essential Background for Mixed Model Power and Precision. 102

4.3 Computing Precision and Power for CRD: An Example. 104

4.3.1 Creation of an Exemplary Data Set and Use of PROC GLIMMIX.. 104

4.3.2 Completion of the Power Calculation. 105

4.4 Comparing Competing Designs I—CRD versus RCBD: An Example. ₁₀₈

4.4.1 Revision of PROC GLIMMIX Power and Calculation Steps. 108

4.4.2 Precision of Treatment Differences with Blocking. 108

4.4.3 Pilot Data to Anticipate Variance Components for Precision and Power Analysis. 109

4.4.4 Precision and Power for Changing Sample Size with Blocked Design. 111

4.5 Comparing Competing Designs II—Complete versus Incomplete ...