Alex, The answer to the second question is yes (that group contrasts are run level_1 - level_2). When the qdec Analysis button is pressed, each contrast matrix is printed to the terminal, something like this: . . . Diff-Demented-Nondemented-Intercept-thickness ----------------------- Does the average thickness differ between Demented and Nondemented? 1.000 -1.000; . . . so you can confirm which is being subtracted.
Per your first question, in a future version of qdec, the form of the question will include the extension ", regardless of <continuous factor>", to help clarify the meaning. For example, your example question would read: "Does the average thickness differ between grp1 and grp2, regardless of age?" Nick On Tue, 2007-10-30 at 20:01 -0400, Doug Greve wrote: > The answer to the first question is yes, it will covary (or "regress > out") for the continuous variable. For question #2, I also believe that > the answer is yes, though Nick may be able to say definitively. > > doug > > Alexander Fornito wrote: > > >Hi all, > >If i run a model in qdec that inludes 1 discrete and 1 continuous factor, > >does the output for the group contrast covary for the continuous variable? > >For example, if I want to compare two groups, and include group as my > >discrete factor and age as a continuous factor, will the output for the > >group contrast (Does the average thickness differ between grp1 and grp2?) > >covary for age? > >I've notice that running it without continuous factors leads to different > >results, so I just wanted to confirm this is the case. > > > >Also, just wanted to check that group contrasts are run as level_1 - > >level_2, so that positive values (i.e., red-yellow) indicate level_1 > > >level_2. > > > >Thanks for your help, > >Alex > >_______________________________________________ > >Freesurfer mailing list > >Freesurfer@nmr.mgh.harvard.edu > >https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer > > > > > > > > > _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
