Dear SPMers,
In SPM8, I am trying to run a paired ttest with one covariate - a vector of numbers ranging from 0 to 15.5.
Each time I try to run it, I get an error below:
Running 'Factorial design specification'
Failed 'Factorial design specification'
Error using spm_meanby (line 31)
row dimension mismatch between inputs
In file "E:\kasias\spm8\spm_meanby.m" (v1143), function "spm_meanby" at line 31.
In file "E:\kasias\spm8\config\spm_run_factorial_design.m" (v4537), function "spm_run_factorial_design" at line 587.
It is surprising, as the vector of covariate is exactly the same length as the number of subjects, and therefore the number of pairs entered into the batch. I saw a couple of emails concering this issue, but non of the solutions are working in my case (restarting SPM, MATLAB, computer did not work). I have already runned a simple regression with this covariate on the scans from one timepoint and it worked perfectly well. The error occurs when I want to compare data from 2 timepoints using paired ttest and including the covariate.
Please, let me know how to deal with it.
