Manja, I think FDR can be different for each hemisphere since they are taken apart during processing.
Best Regards, Pedro Paulo Jr 2008/8/27 Manja Lehmann <[EMAIL PROTECTED]> > Hi, > > We've noticed that FDR correction produces different p-values for the left > and right hemispheres. We found that this issue was observed previously and > an email was sent to the mailing list (see below), however, no answer was > received. We wondered if anybody has noticed this problem before and if > there are any suggestions on how best to deal with it. > > Thanks > Manja > > Hi, > FDR correction for multiple comparisons gives you different p-values for > the left and right hemispheres. It seems really weird to report in a > paper: > a) that you've corrected for the right and left hemispheres separately and > b) that the p-value that gave rise to a corrected probability of .05 was > different for each. > How do people deal with this issue? Take the most stringent p-value and > use it for both hemispheres? Just report that FDR adjusted the p- value to > .05? > > Also, correcting for right and left hemispheres separately assumes that > they are independent observations. Unless you're studying callosotomy > patients (and maybe even if you are) this doesn't seem justified. Are we > supposed to be adjusting p-values accordingly? > > Thanks, > Dara > > > -- > > Manja Lehmann > > Research Assistant > > Dementia Research Centre > > University College London > > Institute of Neurology > > Queen Square > > London WC1N 3BG > > > > [EMAIL PROTECTED] > > Tel: 020 7837 3611 ext. 3962 > > > > P Please consider the environment before printing this e-mail > > > > _______________________________________________ > Freesurfer mailing list > [email protected] > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer > -- ----------------------------------------------------------- Pedro Paulo de M. Oliveira Junior Diretor de Operações Netfilter & SpeedComm Telecom
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