Dear Marco,
it seems from your design that EV's 4 and 5 are on a "subject basis", i.e. for a given subject the value of that covariate is fixed. You cannot combine that with "subject specific" regressors (i.e. paired design) since anything captured by EV 4 or 5 will already have been taken care of by the subject specific regressors.
Just remove 4 and 5 and try again.
Good luck Jesper
On 12 Jul 2011, at 19:27, Marco Loggia wrote:
> Dear all,
>
> I am setting up a design matrix (see attached) in which each of my 54 subjects has a 'pre-' vs 'post-' paired comparison.
> The subjects are divided into three groups (EVs 1-2-3), EVs 4 and 5 are covariates of no interest, and EV6-59 are the individual subjects.
>
> Feat is complaining that "at least one EV is (close to) a linear combination of the others" (see below for more details). However, when I double check the model, this does not seem to be the case. Or am I missing something? Also, editing the design matrix from the GUI is veeeery slow. Is it possible that it is an issue with the size of the design matrix?
>
> Thanks!
> Marco
>
> "Problem with processing the model: Warning: at least one EV is (close to) a linear combination of the others. You probably need to alter your design. (Design matrix is rank deficient - ratio of min:max eigenvalues in SVD of matrix is 2.28634e-17)
> with 54 subjects, divided into 3 groups, each with 2 conditions.
>
> <within-sub.png>
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