The error indicates that the vector you entered as covariate does not
have the right length (two times the total number of subjects).
Depending on what you actually want to do with the ANCOVA, you might
want to use a two-sample t-test after contrasting the within-subject
factor at the first level ([1 1] or [1 -1]) and including the covariate
there (potentially interacting with group).
On 16/06/2019 20:39, Jeff Browndyke wrote:
> Is it possible to run a 2x2 ANCOVA in SPM12? Right now I have subject, group and condition factors in my model.
> I keep on getting the following error when trying to add a covariate to my model:
> 16-Jun-2019 15:34:52 - Running 'Factorial design specification'
> 16-Jun-2019 15:34:54 - Failed 'Factorial design specification'
> Index exceeds matrix dimensions.
> In file "/Applications/Neuroimaging/functional/spm12/spm_design_within_subject.m" (v4837), function "spm_design_within_subject" at line 82.
> In file "/Applications/Neuroimaging/functional/spm12/config/spm_run_factorial_design.m" (v6219), function "spm_run_factorial_design" at line 515.
> No executable modules, but still unresolved dependencies or incomplete module inputs.
> Jeff Browndyke
Guillaume Flandin, PhD
Wellcome Centre for Human Neuroimaging
UCL Queen Square Institute of Neurology
London WC1N 3BG