Well, the second edition of SAS for Mixed Models does address the denominator degrees of freedom. I would recommend ddfm=satterthwaite here; if there were repeated measures, I would recommend Kenward-Rogers. For mean separation tests, you should go through Multiple Comparisons and Multiple Tests Using SAS, 2nd. edition, by Westfall, Tobias and Wolfinger. I would recommend Edward and Berry's simulation method. Steve Denham
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