On 11/19/2012 03:04 AM, Mahinda Yogarajah wrote: > 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. whether it is valid or not depends on what you are trying to conclude. If you want to compare across the tests, I would do the demeaning once across all subjects and not individually for each test. > > 2) Is there a better way of comparing my subgroups to controls ? Not that I can think of > > Thanks. > > Mahinda > > > _______________________________________________ > Freesurfer mailing list > Freesurfer@nmr.mgh.harvard.edu > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer > >
-- Douglas N. Greve, Ph.D. MGH-NMR Center gr...@nmr.mgh.harvard.edu Phone Number: 617-724-2358 Fax: 617-726-7422 Bugs: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting FileDrop: www.nmr.mgh.harvard.edu/facility/filedrop/index.html Outgoing: ftp://surfer.nmr.mgh.harvard.edu/transfer/outgoing/flat/greve/ _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-mail contains patient information, please contact the Partners Compliance HelpLine at http://www.partners.org/complianceline . If the e-mail was sent to you in error but does not contain patient information, please contact the sender and properly dispose of the e-mail.
