[FieldTrip] Non-parametric permutation clustering with 2x2 within subject conditions.

Tom Marshall tom.marshall at psy.ox.ac.uk
Wed Jun 10 15:28:43 CEST 2020


Hi Cay,

It sounds like you want to test whether there is an interaction between your two independent variables ('target' and 'lure').

If so, you should start here: http://www.fieldtriptoolbox.org/faq/how_can_i_test_an_interaction_effect_using_cluster-based_permutation_tests/ , which will help you understand what you can and can't do to test interactions using cluster-based permutation.

If that doesn't help feel free to ask here again.

It is always helpful to provide as much information as possible in your question. For instance, right now I can't tell if you're asking about what kind of test to do, or how to write the code for doing the test, which makes it difficult to give advice.

I hope that's clear and helps you!

Best,
Tom
How to test an interaction effect using cluster-based permutation tests? - FieldTrip toolbox<http://www.fieldtriptoolbox.org/faq/how_can_i_test_an_interaction_effect_using_cluster-based_permutation_tests/>
How to test an interaction effect using cluster-based permutation tests? You can use cluster-based permutation tests for some but not for all interaction effects. Specifically, you can only use them for testing interaction effects in factorial designs with only a single between-subjects factor.
www.fieldtriptoolbox.org

________________________________
From: fieldtrip <fieldtrip-bounces at science.ru.nl> on behalf of Lee, Kyoung Eun <klee773 at gatech.edu>
Sent: 10 June 2020 12:47
To: fieldtrip at science.ru.nl <fieldtrip at science.ru.nl>
Subject: [FieldTrip] Non-parametric permutation clustering with 2x2 within subject conditions.


Dear FieldTrip users,



Currently I’m working on a non-parametric permutation clustering with ft_freqstatistics function.

So far, I just compared two different within-subject conditions (Hit vs. Miss), Therefore, I set “cfg.statistic = 'depsamplesT'”.

And my design is set as below :

subj = 42;

design(1,1:subj) = 1:subj; design(1,subj+1:2*subj)= 1:subj;

design(2,1:subj) = 1; design(2,subj+1:2*subj)= 2;



But now, I want to compare 2x2 within subject conditions (Target-Hit/ Target-Miss/ Lure-Hit/ Lure-Miss).

In this case, what kind of statistic I have to use? How can I change the design?

And lastly, how’s the results look like? (would there be positive and negative clusters?)



Please let me know if you have any suggestion.

Thank you so much,



Best,

Cay








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