That is usually not the way you want to handle dichotomous variables. For example, if you use Male=1 and Female=2, you are implying that Females have a factor of two greater thickness (or whatever) relative to males. Maybe it works if the factor only has two levels. But why not set it up as a discrete factor? QDEC was not really meant to handle a wide range of designs, so you might be better off going to the command line (mri_glmfit) stream
On 11/14/2016 07:03 AM, Dominic Dwyer wrote: > Hi Prof. Greve, > > Thanks for the response and sorry for the confusion. I mean can we use > dichotomous variables in the "Nuisance Factors" box of qdec? i.e., if > we don't explicitly define them as categorical variables. I was > thinking that if it's a GLM then it should be ok? > > We want to do this because we have more than one dichotomous variable > that we want to control for. > > Many thanks, > Dom > > -------------------------------------------------------------------- > *Dom Dwyer, PhD* > Psychiatry & Psychotherapy > LMU Munich > > A: Nußbaumstr. 7, Munich, 80336 > E: dominic.dw...@med.uni-muenchen.de > <mailto:dominic.dw...@med.uni-muenchen.de> > T: +49 (0)89 4400 55880 > > I'm not sure what you mean. Dichotomous variables can be used. Our > tutorial has an example of using gender. > On 11/9/16 5:05 AM, Dominic Dwyer wrote: > > Dear FS experts, > > Sorry for my confusion here, but I'm wondering why dichotomous > nuisance variables (e.g., gender) can't be used in qdec? I was > thinking that if it uses a generalized linear model then it should > be ok? I read other posts and understand why discrete factors > can't be used with more than 2 levels, but was thinking that > dichotomous variables should be different.NB. we're trying to run > a simple two group comparison, but we two dichotomous variables > that we want to control for. > > Many thanks for your help, > Dom > > -------------------------------------------------------------------- > *Dom Dwyer, PhD* > Psychiatry & Psychotherapy > LMU Munich > > A: Nußbaumstr. 7, Munich, 80336 > > E: dominic.dw...@med.uni-muenchen.de <http://med.uni-muenchen.de> > <mailto:dominic.dw...@med.uni-muenchen.de> > > T: +49 (0)89 4400 55880 > > > > _______________________________________________ > 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: https://gate.nmr.mgh.harvard.edu/filedrop2 www.nmr.mgh.harvard.edu/facility/filedrop/index.html Outgoing: ftp://surfer.nmr.mgh.harvard.edu/transfer/outgoing/flat/greve/ _______________________________________________ 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.
