[SciPy-User] stats repeated measures ANOVA

[Peter Tittmann]

Thanks for your reply Josef, sorry for the obscurity, I've third to clarify
below....
On Apr 11, 2011 8:44 PM, <josef.pktd at gmail.com> wrote:
>
> On Mon, Apr 11, 2011 at 10:52 PM, Peter <ptittmann at gmail.com> wrote:
> > All,
> >
> > I would like to determine the effect of  two independent variables (tree
> > size class, and canopy percent cover) which are factor vectors
> > (non-continuous) on the variance between two methods of measuring tree
> > height.
> >
> > I believe this is referred to as two-way repeated measures ANOVA.
>
> As far as I understand ANOVA only tests for differences in means, or
> mean effects, not differences in variances, equality of variances is
> usually a standard assumption for ANOVA.
There's a tutorial on doing it in R here
http://www.r-bloggers.com/r-tutorial-series-two-way-repeated-measures-anova/
but it has a lot of array operations involved which I would preferr to do in
python.
>
> But it's not clear to me what you want to test or estimate, with size,
> cover and method you have actually 3 factors.
> Are the two measuring methods for height used for every tree?
> Do you want the effect of size and cover on the measurement variance
> for each method separately?
> ....?
One method for measurement is field based and the other uses aerial data.
The objective is to determine if the two factors (canopy density and tree
diameter class) explain variance between of the measurement methods (ie
accuracy of the aerial method)
>
> I don't know much about two-way repeated measures ANOVA directly, but
> my guess is that it can be translated into estimating with a linear
> model and doing some heteroscedasticity tests on it.
> statsmodels might have the basis for this, but without more details on
> what exactly you want to estimate or test it's difficult to tell how
> much work this is.
>
> Cheers,
>
> Josef
>
>
>
> >
> > Can anyone refer me to existing scipy (or other) methods for conducting
> > this type of analysis?
> >
> > Best,
> > Peter
> >
> >
> > _______________________________________________
> > SciPy-User mailing list
> > SciPy-User at scipy.org
> > http://mail.scipy.org/mailman/listinfo/scipy-user
> >
> _______________________________________________
> SciPy-User mailing list
> SciPy-User at scipy.org
> http://mail.scipy.org/mailman/listinfo/scipy-user
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.scipy.org/pipermail/scipy-user/attachments/20110411/123c67a2/attachment.html>