Hi,
I processed some patients and controls with TBSS and am now trying to find
the age effect and age*group interaction in randomise. Would someone please
check my design and contrast matrices below? Also, in the design matrix, I
subtracted the mean age from each individual subject's age; is this the
proper way to demean the ages?
Design matrix:
EV1(control) EV2(patient) EV3(age) EV4(age*control) EV5(age*patient)
1 0 4 4 0
1 0 -4 -4 0
0 1 -9.8 0 -9.8
...
...
0 1 -1.2 0 -1.2
0 1 -3 0 -3
1 0 -4 -4 0
1 0 4.3 4.3 0
Contrast matrix:
EV1(control) EV2(patient) EV3(age) EV4(age*control) EV5(age*patient)
control>meth 1 -1 0 0 0
meth>control -1 1 0 0 0
randomise -i all_FA_skeletonised -o tbss -m mean_FA_skeleton_mask -d
design.mat -t design.con -n 100 -c 3 -V
Also, after all permutations (only 100 for quick initial results) are
finished, the following error occurs:
terminate called after throwing an instance of 'NEWMAT::ConvergenceException'
Aborted
Any input on these issues would be greatly appreciated.
Thanks,
Russell
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