I have a set with 60 observations, in four groups t1,t2,m1,m2 each with 15 observations. If I want to compare t1,t2 to m1,m2 or t1,m1 to t2,m2 what I did was to create a new variable so I can group the observations in 2 groups t and m and on the second iteration groups 1 and 2 then I just used a...