If you want to test for an interaction between Age and Weight, you need to create a new covariate which is Age*Weight, then test the sig of this covariate. I would demean Age and Weight for both the inidvidual covaraite and before computing the product.
On 04/12/2018 12:35 PM, David S Lee wrote: > Hi FreeSurfer Experts, > > I have two groups (Male and Female) and two covariates (Age and > Weight). I want to test change of cortical thickness with age and > weight, after removing effects of Group. In other words, is there an > interaction between age and weight, regressing out the effects of groups. > > How can I set up my Design Matrix to test this? > > Thank you, > > -- > David S. Lee > Associate Research Specialist > Center for Healthy Minds > University of Wisconsin - Madison > (608) 890-1115 <tel:%28608%29%20890-1115> > > > _______________________________________________ > 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.
