Hi there,
>
> Dear SPM-ers,
>
> I have set up an ANOVA-design with three levels (see Design Matrix
> attached), and I try to calculate a T-contrast to "substract" the
> fisrt two levels from the third [-1 -1 2].
>
> With former revision of spm worked well, but now it says 'trying to
> define a t that looks like an F'.
>
> Is it a bug, or did I something wrong?
>
Not sure but I guess it a feature :-)
Unless you have strong hypothesis on the effect size of the col 3 (col3
> than average col1 and col2) you would perform an F like [-1 0 1; 0 -1
1] which tests if col3 is > col1 and/or col2 - or if you want even
stronger do [-1 0 1] and [0 -1 1] and perform a conjunction null =
col3>col1 AND col3>col2
Hope this helps
cyril
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