Is running a t-test contrast still valid if I don't have equal numbers in the four groups (Male Treatment, Male Control, Female Treatment, Female Control) or should I be running an F test instead?
Sasha >>> Doug Greve <[EMAIL PROTECTED]> 4/14/2006 3:18 pm >>> Yes, you just need to come up with the the contrast matrix taht tests what you want to test. If the contrast matrix has one row, then it's a t-test. If there are more than one, then it's an F test. You example is actually a t-test, I think, just: (MaleTreatment-MaleControl) - (FemaleTreatment-FemaleControl) for a contrast of: +1 -1 -1 +1 doug Sasha Wolosin wrote: >Dear FreeSurfers, > > I am interested in examining interaction effects between two sets of >classes where each covers all the data, let's say Male/Female and >Treatment/Control. I know mri_glmfit can be used to run t-test >comparisons between groups (e.g. All Treatment vs. All Control , or Male >& Control vs. Male & Treatment), but can mri_glmfit be used to examine >interaction effects between these two sets of classes (for surface >data)? > >my FSGD file looks like this: > GroupDescriptorFile 1 > Class MaleTreatment > Class MaleControl > Class FemaleTreatment > Class FemaleControl > Input subjid1a MaleTreatment > Input subjid1b FemaleTreatment > Input subjid2a FemaleControl > Input subjid2b MaleControl > etc... > >Thanks, >Sasha > >Sasha Wolosin >Research Assistant >Developmental Cognitive Neurology >Kennedy Krieger Institute >707 N. Broadway >Baltimore, MD 21205 >ph: (443) 923-9270 >[EMAIL PROTECTED] > > > >Disclaimer: >The materials in this e-mail are private and may contain Protected Health Information. Please note that e-mail is not necessarily confidential or secure. Your use of e-mail constitutes your acknowledgment of these confidentiality and security limitations. If you are not the intended recipient, be advised that any unauthorized use, disclosure, copying, distribution, or the taking of any action in reliance on the contents of this information is strictly prohibited. If you have received this e-mail in error, please immediately notify the sender via telephone or return e-mail. >_______________________________________________ >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 [EMAIL PROTECTED] Phone Number: 617-724-2358 Fax: 617-726-7422 In order to help us help you, please follow the steps in: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
