If you have SPM.mat files you can calculate efficiency with the
following lines of matlab code, where X is the design matrix taken
from SPM.mat and c is your chosen contrast vector. When forming your
contrast vector remember to take into account the mean, which was the
last element in the contrast vector below.
X=SPM.xX.X;
c=[1 -1 0];
disp( 1 / (c*inv(X'*X)*c' ) );
Jim Lee
Univ. of Utah
Hi all,
Is there any simple way of calculating and comparing design
efficiencies using spm?
For example, I want to compare different designs before I do them. So
I specify them using spm but entering the time of trial onset.. Now I
have different spm.mat but I hope that I can find a practical way to
compare them and find the most efficient one.
Any help please!
Thanks
AS
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