Dear SPM users,
I am performing a longitudinal analysis with VBM8. I have two groups (patients and controls) and two MRI for each subject. I used the spm manual to begin stat!
Factor 1: subject
Factor 2: group
Factor 3: time
However I don't understand how to enter contrast weights. I read the paper of Glascher and Gitelman to understand better flexible factorial and how enter contrats weights! But I don't really understand the different possibilities I have!
1/ What is the difference between testing the main effect of group or the main effect of condition?
2/ What is the mean of the interaction group x condition?
3/ When I have to use the "test for single regressor in one group" or "test for two single regressor in both groups"?
4/ What the mean of "average effect of condition"?
I am not an expert in stat at all! I hope somebody can help me!
Thanks,
C.
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