Introduction to Power and Sample Size Analysis

Coverage of Statistical Analyses

The GLMPOWER procedure covers power analysis for Type III F tests and contrasts of fixed effects in univariate and multivariate linear models. For univariate models, you can specify covariates, which can be continuous or categorical. For multivariate models, you can choose among Wilks’ likelihood ratio, Hotelling-Lawley trace, and Pillai’s trace F tests for multivariate analysis of variance (MANOVA) and among uncorrected, Greenhouse-Geisser, Huynh-Feldt, and Box conservative F tests for the univariate approach to repeated measures. Tests and contrasts that involve random effects are not supported.

The POWER procedure covers power analysis for the following:

  • t tests, equivalence tests, and confidence intervals for means

  • tests, equivalence tests, and confidence intervals for binomial proportions

  • multiple regression

  • tests of correlation and partial correlation

  • one-way analysis of variance

  • rank tests for comparing two survival curves

  • Cox proportional hazards regression

  • logistic regression with binary response

  • Wilcoxon Mann-Whitney rank-sum test

The Power and Sample Size application covers a large subset of the analyses in the GLMPOWER and POWER procedures.