Hi Doug, Thanks... Presumably I'd just leave each possible pair of groups at a time in the qdec table, and delete rows corresponding to subjects of the remaining group? And then do stats on, e.g. "long.thickness-rate" to compare rate of change between the current pair of groups? Doesn't variability across all 3 groups somehow have to be accounted for?
Tudor On 16 June 2014 20:38, Douglas Greve <gr...@nmr.mgh.harvard.edu> wrote: > > Yes, you could do each separately. > doug > > > > On 6/16/14 8:10 PM, Tudor Popescu wrote: > > Dear FS list, > > I have a data set with 3 groups (2 treatments, 1 control), each with > equally-spaced time-points (pre and post structural scan). I've done the 3 > longitudinal pre-processing steps, and stage#1 of the two-stage model, and > I would prefer to run stage#2 (cross-sectional analysis of the difference) > with QDEC as opposed to with mri_glmfit. > > I know that QDEC is meant for 2 groups, but I see that designs with 4 or 6 > groups can be analysed with QDEC (as per this > <https://surfer.nmr.mgh.harvard.edu/fswiki/FsgdExamples> FSGD examples > page) whereas designs with 3 groups cannot be. It seems to me that an even > number of groups is QDEC-able while an odd number isn't, but is there any > workaround so that I can still use QDEC? Perhaps if I only do pairwise > comparisons one at a time, i.e. treatment1 vs control and treatment2 vs > control? > > Many thanks! > Tudor > > > _______________________________________________ > Freesurfer mailing > listfreesur...@nmr.mgh.harvard.eduhttps://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. > >
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