[pymvpa] Z-scoring raw data

[Yaroslav Halchenko]

and depending on how you want to interpret your data z-scoring against
rest condition might have clearer 'meaning' that standartization of the
whole time series happen you to look at the actual values

but, as you have observed, since rest-condition is scarser in # of
samples than the whole time series, its stat estimates are less reliable
thus there could indeed be negative impact on the generalization
performance.

On Thu, 19 Apr 2012, Michael Hanke wrote:
> > am I am wondering if you have found it beneficial to z-score in that way or
> > if just doing a simple z-score on the entire time course (per run) provides
> > similar classification accuracy.

> Main reason of doing that in the tutorial was to show that it is
> possible ;-) it wasn't meant to be an advice that it should always be
> done this way.
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