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Data Analysis Papers

Updates to SASŪ Power and Sample Size Software in SAS 9.2
Watson, Wayne E.; SAS Institute, 2008

Abstract

Procedures for power analysis and sample size determination were introduced in SAS/STAT® 9.1 along with a Web application for performing these analyses. SAS/STAT® 9.2 adds analyses for several new designs, enhances some existing analyses, and replaces the Web application with a desktop application for your PC.

The new analyses include logistic regression; confidence intervals, equivalence tests, and noninferiority tests for a binomial proportion; and the Wilcoxon Mann-Whitney test for two distributions. These new analyses join the ones already available with SAS/STAT® 9.1: general linear univariate models, one-way ANOVA, multiple regression, t tests, confidence intervals and equivalence tests of means, tests of proportions, and survival rank tests.

SAS® Power and Sample Size (PSS) 3.1 is an application that comes with the SAS/STAT® product but is installed separately. PSS 3.1 supersedes the PSS 2.0 Web application that was offered with SAS/STAT® 9.1. It provides a pointand- click interface to the power analysis and sample size capabilities in SAS/STAT® software. Results include computation tables, graphs, and narratives (text descriptions of individual analysis scenarios). PSS 3.1 offers all of the analyses that were available in PSS 2.0 in addition to the analyses that are new for SAS® 9.2. Projects that were created with PSS 2.0 can be used by PSS 3.1.

This paper highlights the new features of the procedures and describes the new desktop application.