The POWER Procedure

Syntax: POWER Procedure

The following statements are available in the POWER procedure:

The statements in the POWER procedure consist of the PROC POWER statement, a set of analysis statements (for requesting specific power and sample size analyses), and the PLOT statement (for producing graphs). The PROC POWER statement and at least one of the analysis statements are required. The analysis statements are LOGISTIC , MULTREG , ONECORR , ONESAMPLEFREQ , ONESAMPLEMEANS , ONEWAYANOVA , PAIREDFREQ , PAIREDMEANS , TWOSAMPLEFREQ , TWOSAMPLEMEANS , TWOSAMPLESURVIVAL , and TWOSAMPLEWILCOXON .

You can use multiple analysis statements and multiple PLOT statements. Each analysis statement produces a separate sample size analysis. Each PLOT statement refers to the previous analysis statement and generates a separate graph (or set of graphs).

The name of an analysis statement describes the framework of the statistical analysis for which sample size calculations are desired. You use options in the analysis statements to identify the result parameter to compute, to specify the statistical test and computational options, and to provide one or more scenarios for the values of relevant analysis parameters.

Table 77.1 summarizes the basic functions of each statement in PROC POWER. The syntax of each statement in Table 77.1 is described in the following pages.

Table 77.1: Statements in the POWER Procedure




Invokes the procedure


Likelihood ratio chi-square test of a single predictor in logistic regression with binary response


Tests of one or more coefficients in multiple linear regression


Fisher’s z test and t test of (partial) correlation


Tests, confidence interval precision, and equivalence tests of a single binomial proportion


One-sample t test, confidence interval precision, or equivalence test


One-way ANOVA including single-degree-of-freedom contrasts


McNemar’s test for paired proportions


Paired t test, confidence interval precision, or equivalence test


Displays plots for previous sample size analysis


Chi-square, likelihood ratio, and Fisher’s exact tests for two independent proportions


Two-sample t test, confidence interval precision, or equivalence test


Log-rank, Gehan, and Tarone-Ware tests for comparing two survival curves


Wilcoxon-Mann-Whitney (rank-sum) test for 2 independent groups

See the section Summary of Analyses for a summary of the analyses available and the syntax required for them.