[Eeglablist] ERSP graphs in microvolts (not in dB)?
arno delorme
arno at ucsd.edu
Tue Sep 16 12:15:10 PDT 2008
Dear Zach,
> Thanks for the info - I think a lot of us have been wondering about
> this one ( I actually asked pretty much the same question before
> your response but it hasn't showed up in the archive yet). However,
> the trouble that I am still having is that I'm wondering what is the
> best way to approach this data for (parametric) statistical
> analysis. That is, the default output is in dB which is on a
> logarithmic scale and thus not appropriate for parametric stats.
Parametric statistics are applicable whenever the data has a
probability distribution which is close to gaussian. I do not know if
absolute amplitude has a more gaussian distribution than log power.
You should test it.
> There is the possibility of nonparametric tests, but my options may
> be more limited than those of parametric techniques (plus they seem
> to be somewhat frowned upon in some circles).
Non-parametric ootstrap or permutation test are the norm for single
subject analysis. For multi-subject analysis, there are applicable
too. If should test if your data is gaussian to apply a parametric test.
Best,
Arno
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