Hi there,
I just want to make sure that I have the appropriate design for an ANCOVA I am trying to set up for a VBM analysis. I have 4 groups (control, disease 1, disease 2, disease 3) and want to include demeaned age (EV5) and demeaned interhemispheric volume (EV6) as nuisance variables. I want to perform F-tests to see if there are any differences between the groups. For ease of displaying, I've included 2 subjects from each group and hypothetical values for age and volume.
Does the following look right for what I want to accomplish?
DESIGN
Group EV1 EV2 EV3 EV4 EV5 EV6
1 1 1 0 0 3 -200000
1 1 1 0 0 3 -150000
1 1 0 1 0 5 -100000
1 1 0 1 0 2 -50000
1 1 0 0 1 -1 50000
1 1 0 0 1 -4 100000
1 1 0 0 0 -6 150000
1 1 0 0 0 -2 200000
CONTRASTS
Title EV1 EV2 EV3 EV4 EV5 EV6 F1
X A-D 0 1 0 0 0 0 X
X B-D 0 0 1 0 0 0 X
X C-D 0 0 0 1 0 0 X
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