Dear Karl and spm'ers,
We want to analyze a PET study comparing two groups: 4 patients in group 1
and 16 in group 2. For each patient, there are two different conditions
(Awake and Sleep) and one covariate. Furthermore, there is only one scan
for each subject/condition. We would like to test for the differences
between sleep and awake between the two groups. I have a few questions:
(1.) If there was no covariate included, it seems that the contrast
vector should be [1 -1 -1 ]. How does one adjust for the covariate?
(2.) Is there a test for a covariate effect in SPM96?
Thanks.
Hernando Ombao
U of Pittsburgh
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