[pymvpa] null classification performance in the presence of strong univariate signal??

[Nick Oosterhof]

On Sep 11, 2014, at 9:34 PM, David Soto <d.soto.b at gmail.com> wrote:

> now my question is - would not zscoring solve the issue you mentioned?

Quite possibly so, but the only way to know is to try.

> 
> I realise is not possible to zscore by chunks because these are the subjects
> and only 2 samples....but I tried other zscoring schemes (i.e. by task condition
> A vs. B or globally across the 38 samples) and still get null MVPA performance

That's not impossible, but still a bit curious.

> 
> would there be any advantage in trying the tstats or zstats instead of the betas
> as the former are already zscored?

It could, with t-stats there is usually less of an issue with outlier values.