Hi,
Demeaning (manual or automatic) is necessary, since you model the mean in EV1
already. So you have only two options:
1. either you enter raw data and use the -D option (automatic)
2. or you enter demeaned data and you do not have to use -D option (manual)
(It makes no sense - however, make no harm either - using -D option on
demeaned data, since the mean is 0. As a result, you demeaned data will be
untouched.)
I hope it helps,
Auer, Tibor M.D. Ph.D.
Biomedizinische NMR Forschungs GmbH
am Max-Planck Institut für Biophysikalische Chemie
Am Fassberg 11
37077 Göttingen
Germany
Phone/Work: +49-(0)551-201-1725
Phone/Home: +49-(0)551-387-0076
Mobile: +49-(0)176-8012-7921
Mail: [log in to unmask]
> -----Original Message-----
> From: FSL - FMRIB's Software Library [mailto:[log in to unmask]] On
> Behalf Of Mauro Serra
> Sent: Wednesday, July 04, 2012 5:36 PM
> To: [log in to unmask]
> Subject: [FSL] demean in TBSS
>
> HI,
>
> I'm new in fsl DTI analisys, I'm not shure if I have understood when I need
to
> demean my data.
>
> I'm performing a TBSS analysis within subjects, with only one EV: I'm
> correlating FA and a behavioural measure.
>
> I have posted the design matrix and the contrast matrix, my questions are:
>
> 1) Should I use randomize with the option -D like in this script:
> randomise -i all_FA_skeletonised -o tbss -m mean_FA_skeleton_mask -d
> design_nco.mat -t design_nico.con -n 500 -D --T2 or not?
>
> 2) if I have to use -D should I insert in the design matrix the behavioural
> demeaned data? or should I insert the "row" data and the -D option will do
> everything automatically?
>
> 3) if I don't have to use the -D option in the script, what about the
> behavioural data? should I write in the design matrix the demeaned
> behavioural score or row score?
>
> Thanks in advance for the help, and I'msorry if my question looks stupid
but
> I'm really stuck on it!
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