An Introduction to Statistical Power Calculations for Linear Models with SAS 9.1

In Version 9.1 SAS® introduced two new procedures that compute power under a variety of statistical designs which are very effective study planning tools. In particular, this paper focuses on how SAS computes power for continuous response data. PROC POWER computes power for T-tests, one-way ANOVAs, correlations, and regression models. PROC GLMPOWER computes power for ANOVA and ANCOVA models with one or more between-subject factors and continuous covariates. PROC MIXED is shown to be yet another very effective study planning tool as data inputs can be manipulated to generate power calculations for comparisons of means from linear models of greater complexity, such as repeated measurements. The essential points of prospective power analysis will also be reviewed and contrasted with some of the fallacies that underlie retrospective power analysis.

Paper: 

Robin High - Statistical Power Calculations for Linear Models.pdf