For the interaction it would be 0.5 -0.5 -0.5 0.5
On 5/9/17 8:32 AM, Laura Ferrero Montes wrote: > > Thank you for the information. I just want to be sure if I have > understood it properly. > If I had two groups and two sites, my design matrix would be like: > > GroupDescriptorFile 1 > Class PatientsGroup1 > Class PatientsGroup2 > Class ControlsGroup1 > Class ControlsGroup2 > > If I want to test for the effect of group, contrast matrix would be: > 0.5 -0.5 0.5 -0.5 > > If I want to test for the effect of site, contrast matrix would be: > 0.5 0.5 -0.5 -0.5 > > Finally, in case of interaction test, how contrast matrix would be? > > > > > > Douglas N Greve <gr...@nmr.mgh.harvard.edu> escribió: > >> You should make sure to have a balanced design (ie, approx the same pats >> and cons at each site). Then include site as a regressor, ie, if you had >> two groups and two sites, you would have four regressors. You could >> then test for the effect of group, the effect of site, and the >> interaction. If there is an interaction, then it is hard to interpret >> the differences between groups. >> > > > _______________________________________________ > 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 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.
