Dear experts,
I've been reading through the tutorial for group analysis, but I am still a little confused about the contrasts and want to make sure that my contrast is set properly for what I'm interested in looking for. I've made my fsgd file, which contains three groups: ADdiagnosisGroup1, ADdiagnosisGroup2, ADdiagnosisGroup3, and one continuous variable: symptom duration. I want to test if thickness differs between groups controlling for symptom duration. I set my contrasts to: [1 0 -1 0 0 0], [1 -1 0 0 0 0], [0 1 -1 0 0 0]. Since there isn't an fsgd example for 3 groups (1 factor, 3 levels), and one covariate, I wasn't sure if this is correct.
Thanks in advance, Meghan
Meghan McGwier Postbaccalaureate IRTA Fellow Molecular Imaging Branch National Institute of Mental Health Phone: 301-451-2038 Fax: 301-480-3610