[pymvpa] effect of signal on null distributions

J.A. Etzel jetzel at artsci.wustl.edu
Wed Feb 20 21:11:37 UTC 2013

Ben Acland (who recently joined our lab) ran this in pyMVPA, and it made 
a big difference in the resulting null distributions: they now are 
pretty much the same (permute training-only and permute both) even 
though the true-labeled accuracy changes drastically with the amount of 

The post (with a bit more detail) is 

And here is a direct link to the results image 

So, yep, how we simulate the data really makes a difference.


On 2/13/2013 5:06 PM, J.A. Etzel wrote:
> What do the null distribution for different amounts of signal look like
> if you try the simulations making the data as I describe (values from
> two normal distributions with a small difference in mean but same
> standard deviation)?

Joset A. Etzel, Ph.D.
Research Analyst
Cognitive Control & Psychopathology Lab
Washington University in St. Louis

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