You have done the right thing, but you need to know a little more. When QDEC says "mean thickness" it really means the thickness at age=0, so it is extrapolating the results back to age=0. Since you have a covariate and you are using DODS, you have to specify an age at which to do the test (you can't actually test the means with the covariate). If you demean the covariate, you will test it at age=mean age. Alternatively, you can use DOSS to model one slope across both groups and test for the difference in intercept (which will be age-independent with DOSS).
doug johanna feiler wrote: > Dear Freesurfers, > > > in my qdec analysis I want to compare > my patients group with a control group. The analysis should be > corrected for age effects, so I used group as discrete factor and age > as covariate. If I choose „Does the average thickness differ > between the two groups“, how can I interpretate a significant > result in a certain region? > Does it mean: „The mean thickness in > this region differs between both groups significantly, correcting for > age effects“? > I got some highly significant results, > however the groups' means don't seem to differ that much, however, > the groups' trends seem to be quite different. > So which statistical test is implemented ins qdec? > > > Any help will be appreciated! > > Thanks a lot, > Johanna Feiler > ___________________________________________________________ > GRATIS für alle WEB.DE-Nutzer: Die maxdome Movie-FLAT! > Jetzt freischalten unter http://movieflat.web.de > > _______________________________________________ > 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 _______________________________________________ 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.
