As long as you sample is randomly from populations, with 1000 samples and central limited theory, the sample means are normally distributed. If you want to test mean difference, the proc ttest will give you all results.

HTH

%let randomF=rannor;

data t1; do i = 1,2; do j= 1 to 1000; x_&randomF=i*&randomF(123)+i; output; end; end; run;

proc ttest data=t1; class i; var x:; run;

Thanks so much. But, I used proc univariate to check normality and the results suggested non normality. I am a bit confused. Once I have large samples, by the central limit theoreme, should I assume normality even if the proc univariate suggests non normality?

Thanks