Dear Experts,
I have a two groups - a control group and patient group. The patient group can also be divided into 4 subgroups (but not control gp). Both groups are evenly split between male and female. So far I have compared the patient and control groups as a whole (age and icv as continuous/nuisance variables) but now i want to compare each of the subgroups to controls. I have tried doing this in qdec very crudely by running 4 analyses in qdec where I exclude all the subgroup cases execpt for those belonging to the subgroup I am looking at. My questions are
1) Is this valid (I would correct for the multiple tests) ? How does qdec cope with exclusions given that variables (age) have been demeaned across a whole group.
2) Is there a better way of comparing my subgroups to controls ?
Thanks.
Mahinda