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 COXREG , 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 89.1 summarizes the basic functions of each statement in PROC POWER. The syntax of each statement in Table 89.1 is described in the following pages.

Table 89.1: Statements in the POWER Procedure

Statement

Description

PROC POWER

Invokes the procedure

COXREG

Cox proportional hazards regression

LOGISTIC

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

MULTREG

Tests of one or more coefficients in multiple linear regression

ONECORR

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

ONESAMPLEFREQ

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

ONESAMPLEMEANS

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

ONEWAYANOVA

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

PAIREDFREQ

McNemar’s test for paired proportions

PAIREDMEANS

Paired t test, confidence interval precision, or equivalence test

PLOT

Displays plots for previous sample size analysis

TWOSAMPLEFREQ

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

TWOSAMPLEMEANS

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

TWOSAMPLESURVIVAL

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

TWOSAMPLEWILCOXON

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.