Dear Doug, Many thanks for reply. Given the age-group interaction, and the fact that even when age is demeaned it simply means a difference in thickness will be tested for at age=mean age (as opposed to age=0) can I at least interpret the findings when using DODS model with age as a nuisance factor by saying that the difference in thickness between groups represents the difference between groups at the mean age across both groups.
Beyond that limited interpretation, is there any other way to analyse the data ? Is there a another model I could use ? My age-group interactions are in a different location to the group differences - does this make any interpretation of group differences more robust ? Thanks. Mahinda _______________________________________________ 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.