Proc Ttest

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Proc ttest is used to test the hypothesis of equality of means for two normal populations from which independent samples have been obtained. The test statistic is computed under the hypothesis that the two populations have equal variances, and an approximate test statistic is computed under no assumption about the equality of variances. Typical invocation is

proc ttest data=second;
     class type;
     var x y;
run;

THE CLASS SPECIFICATION IS REQUIRED. The class statement specifies a variable (here type) in the data set which takes exactly two values. The values of this class variable define the two populations to be compared.

The optional var statement restricts comparisons to the variables listed; if not used, all variables in the data set (execpt the class variable) are compared pairwise.

For further information see the online help under SAS SYSTEM HELP--MODELING & ANALYSIS TOOLS--DATA ANALYSIS--(analysis of variance) TTEST or the SAS/STAT User's Guide volume 2.

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Copyright © 1997 by Jerry Alan Veeh. All rights reserved.