Introduction to Analysis of Variance Procedures

PROC TTEST for Comparing Two Groups

If you want to perform an analysis of variance and have only one classification variable with two levels, you can use PROC TTEST. In this special case, the results generated by PROC TTEST are equivalent to the results generated by PROC ANOVA or PROC GLM.

You can use PROC TTEST with balanced or unbalanced groups. In addition to the test assuming equal variances, PROC TTEST also performs a Satterthwaite test assuming unequal variances.

The TTEST procedure also performs equivalence tests, computes confidence limits, and supports both normal and lognormal data. If you have an AB/BA crossover design with no carryover effects, then you can use the TTEST procedure to analyze the treatment and period effects.

The PROC NPAR1WAY procedure performs nonparametric analogues to t tests. See ChapterĀ 16: Introduction to Nonparametric Analysis, for an overview and ChapterĀ 83: The NPAR1WAY Procedure, for details on PROC NPAR1WAY.