Hello everybody!
I just need a small precision for statistical analysis. I would like to compare the slope of regression between two groups. Therefore I made my fsgdf like that:
GroupDescriptorFile 1 Title Thickness comparison Class Control CLASS Patient Variable Age Input subj1 Control 10 Input subj2 Control 15 Input subj3 Control 20 Input subj4 Patient 10 Input subj5 Patient 15 Input subj6 Patient 20 ....
And the estimation step with DODS resulted in a design matrix with 4 columns. How do I have to compute the contrast to answer the following question: do cortical thickness decrease more steeply with age in the patient than in the control group? It should be something like 0 0 1 -1 ? (and 1 -1 0 0 will answer to the question: is there any group difference in thickness with age being regressed out?).
Thank you very much for your help!
Marie Schaer