dear all
how could I correct my groups comparison for a covariate?.
should I insert a column as the third one, moving rightwards all the others?
as following...
1 0 a1 +1 0 0 0
1 0 b1 0 +1 0 0
1 0 a2 -1 0 0 0
1 0 b2 0 -1 0 0
0 1 c1 0 0 +1 0
0 1 d1 0 0 0 1
0 1 c2 0 0 -1 0
0 1 d2 0 0 0 -1
with a1 & a2 the values of that var for timepoint1/2
considering the possibility to test different nuisance variables, or evaluate the interaction between groups and such variables, I think it would be easier to calculate the within session differences for each subject, and then pass the NUM_SUBJ copes to a 3rd level feat.
would this model be correct to calculate session differences?
s11 1 0 0 0
s12 -1 0 0 0
s21 0 1 0 0
s22 0 -1 0 0
s31 0 0 1 0
s32 0 0 -1 0
s41 0 0 0 1
s42 0 0 0 -1
c1 1 0 0 0
c2 0 1 0 0
c3 0 0 1 0
c4 0 0 0 1
thanks in advance.
Alberto
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