AW: st: RE: Re: standardized betas in Prais-Winsten Regression

[Schöler, Lisa <lschoeler@wiwi.uni-frankfurt.de>]

Hi,

it is not surprising that R2, F statistics etc. don't change. In my case the coefficients didn't change.
I guessI understood you advice wrong, I thought that 
.center varlist
with SSC center would be the right thing to get the z-transformation.
Thanks again for your help.

Best
Lisa

________________________________________
Von: owner-statalist@hsphsun2.harvard.edu [owner-statalist@hsphsun2.harvard.edu]" im Auftrag von "Christopher Baum [kit.baum@bc.edu]
Gesendet: Samstag, 23. Oktober 2010 01:42
Bis: statalist@hsphsun2.harvard.edu
Betreff: re: st: RE: Re: standardized betas in Prais-Winsten Regression

<.>
Lisa said

I centered all my variables and ran the Prais-Winsten Regression with the centered variables. The coefficients are the same for uncentered and centered variables. I think that this can't be true. Does anyone know why this problem occurs?


Actually if you want beta coefficients, you want to not only center them but z-transform them, that is, subtract the mean and divide by the sd. Subtracting constants from y and x doesn't change their correlation.

But z-transforming is a linear transformation, and regression of a lin.transf.(y) on a lin.transf.(x) doesn't change r^2. F, t-stats, etc. So why should this be surprising?

Kit

Kit Baum   |   Boston College Economics & DIW Berlin   |   http://ideas.repec.org/e/pba1.html
                              An Introduction to Stata Programming  |   http://www.stata-press.com/books/isp.html
   An Introduction to Modern Econometrics Using Stata  |   http://www.stata-press.com/books/imeus.html


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