Programming the statistical procedures from SAS

TTest with small unequal sample size

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Occasional Contributor
Posts: 5

TTest with small unequal sample size

I am trying to compare means of two groups.  The sample size for each group is small (between 9 and 15) and the sample size for each group is not the same.  I have been using proc ttest and looking at the satterthwaite correction p value. The variances are equal (normality is a little off), but I read somewhere that satterthwaite corrects for both variance issues as well as unequal sample sizes. I have also been using proc npar1way and looking at the Wilcoxon results, which I think weights by sample size as the default.  Am I on the right track?  Any advice is appreciated.  Thanks. 

Super User
Posts: 10,880

Re: TTest with small unequal sample size

With samples that small I personally would lean heavily on the nonparametric approaches.

Super User
Posts: 18,599

Re: TTest with small unequal sample size

Besides non-parametric, I would also be relying heavily on knowledge of the data and make sure to include confidence intervals.
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