I need some help either understanding the exact procedure of the permutation cluster test or finding a mistake in my code:
I run mne.stats.permutation_cluster_1samp_test() to find significant activity in waveforms that I extracted from a label.
Now I realized, that the resulting p value is the exactly same for quite some of the conditions I tested, but not all of them.
I suspected some kind of copy & paste error in my code, but I cannot find any. I also double checked the input data: it is different for each condition.
I use the function in the following way:
F1, cluster1, p1, H01= mne.stats.permutation_cluster_1samp_test(A[:,:,cond], n_permutations=5000, tail=0)
With A (the waveforms of each subject) having the dimensions (subjects x time x conditions) and “cond” would be replaced with a different index for each condition.
Usually I do this in a loop, but the error(?) occurs also when I test it for two conditions manually.
In case it is necessary: I’m using Ubuntu 16 and tried with MNE 17.0 and 20.0
Does anyone have an idea or explanation for that behavior?