Dear Eelco years ago i posed a similar question on the FS email list
https://mail.nmr.mgh.harvard.edu/pipermail//freesurfer/2011-November/021386.html a part of the response is below >>> The other question is how mri_glmfit estimates the variance. Because I have >>> only one subject in the patient group, there is not variance in that group >>> and therefore I guess mri_glmfit used pooled (across both groups) estimates >>> of variance, isn't it? >>> >>> >> Yes, it uses pooled estimates. >> >> doug if you are concerned with respect to the variance estimates, it does not matter because variance is estimated pooledly, i.e. across both groups. hope this helps Cheers Jürgen ----------------------------------------------------------------------------------------------------- University of Zurich Dr. Jürgen Hänggi, Ph.D. Department of Psychology Division Neuropsychology Binzmuehlestrasse 14, PO Box 25 8050 Zurich, Switzerland 0041 44 635 73 97 (phone office) 0041 76 445 86 84 (phone mobile) 0041 44 635 74 09 (fax office) BIN 4.D.04 (office room number) j.haen...@psychologie.uzh.ch (email) http://www.psychologie.uzh.ch/neuropsy/ (website) http://www.juergenhaenggi.ch (private website) This e-mail (and any attachment/s) contains confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorised copying, disclosure or distribution of the material in this e-mail is strictly forbidden. ----------------------------------------------------------------------------------------------------- Am 13.10.2016 um 15:56 schrieb Eelco van Duinkerken: > Hi all, > > I am using FS with data from 2 different studies that were acquired on the > same MRI-machine with the same T1 and FLAIR sequences. Unfortunately, the > group sizes are not very balanced, with 31 controls, 16 obese and 32 diabetes > patients. > > Is the GLM for thickness used in FS very sensitive to this unequal group size? > > > Thanks for the help, > > Eelco > _______________________________________________ > 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.
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