[FieldTrip] Permutation test design matrix for grand-averaged ERPs
e.spaak at donders.ru.nl
Tue Oct 23 14:59:26 CEST 2018
You can't do permutation statistics if you've already consumed the
degrees of freedom you want to do statistics across (i.e., subjects in
Did you use cfg.keepindividual = 'yes' in the call to
ft_timelockgrandaverage? If so, then the design matrix should be
specified exactly as in the tutorial; just as if you had been using
the individual subjects' data structures. If not, then indeed you only
have a grand-average left, and no permutation stats can be performed.
On Tue, 23 Oct 2018 at 14:04, Kate Stone <katemsto at gmail.com> wrote:
> Hi all,
> I've been following the tutorial here to do a time-locked perm test on ERP data: www.fieldtriptoolbox.org/tutorial/cluster_permutation_timelock
> I have computed grand averages for my two conditions and am using indepsamplesT with ft_timelockstatistics(cfg, GA_1, GA_2).
> But what should the design matrix be? The example in the tutorial doesn't apply as I am using grand averages and the reference for ft_timelockstatistics doesn't mention the design matrix, although it is definitely required. I have tried design = [1,2], but this doesn't seem to give sensible results.
> Thanks in advance,
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