> > Rich Ulrich wrote:
> me >
> > > > Plus, I've run
the multiple
> > > > regression without the transform and seen only about a 5%
difference
> > > > (not much).
> > >
> > > - damned if I know what that sentence means. You mean, like,
> > > accounting for 99% of the variance, instead of 94%? -- that
means "5%"
> > > by two different criteria.
>
> anthony >
> > Yes, exactly. If I use a square root transform, the variable
accounts for 99%
> > of the variance and if I don't (i.e. just use the raw spike rates)
it accounts
> > for 94% of the variance.
This reminds me of a data set (apparently due to H.J. Jerison
("Evolution of the Brain and Intelligence", NY, 1973) and also
available in Hand _et_al_'s "Handbook of small data sets" (#290,
p.232)) involving brain and body weights of animals. Regression
without transformation yields a mild negative correlation (-0.005),
but after a log transformation on both axes the correlation becomes
0.779.
-Robert Dawson
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