I am trying to run a 2-way anova with my 2 x variables being speed and replicate. When I test the main effects of speed and replicate alone, I am able to produce output that gives me p values however when I try to test speed*replicate in my model my output fails to give me any p values. I am not sure if my data set is too small but my degrees of freedom are 3 and 5 and N = 25.  My coding is found below, if anyone could assist me with this I would really appreciate it, thanks Rakesh Title Adult Fatmucket CR vs Speed; data first; input replicate 1. +1 speed 2. +1 cr 6.; cards; proc print data=first; title 'Speed Data'; run; Title 'Analysis of variance'; proc mixed covtest; class replicate speed; model cr=speed replicate speed*replicate; lsmeans speed; run; ... View more