Dear Feng,
The non-sphericity options correspond to different sets of variance
components stored in SPM.xVi. In your case, for a two-sample t-test,
unequal variance will set two variance components (ie numel(SPM.xVi.Vi)
is 2).
The actual function generating the variance components for given
non-sphericity assumptions is spm_get_vc.m but you should use the high
level functionality of the batch interface:
matlabbatch{1}.spm.stats.factorial_design.des.t2.variance = 1;
% 1 for unequal and 0 for equal
Best regards,
Guillaume.
On 01/06/18 02:25, chenhf_uestc wrote:
> Dear SPM experts,
>
> I perform two-sample t test using SPM12 with equal and unequal variance.
> I am wondering which variable (attached) in SPM.mat save these two
> options? In addition, which part of code in spm_spm.m could be used to
> switch the option of unequal or equal variance? Because I would like to
> implement a batch model.
>
>
> Any help would be greatly appreciated!
>
> Best,
> Feng
--
Guillaume Flandin, PhD
Wellcome Centre for Human Neuroimaging
University College London
12 Queen Square
London WC1N 3BG
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