Re: AW: AW: st: AW: beta coefficients for interaction terms

[lschoele@rumms.uni-mannheim.de]

I got different results first, but trying it again gave me the same results.
According to the book "Data analysis with stata" from Kohler and  
Kreuter, you are not supposed to use
reg mpg headroom length ia2, beta
you are supposed to use
reg smpg shead slength sia2
for interaction effects, but if I get the same beta coefficients, why  
is it wrong to use reg mpg headroom length ia2, beta? That confuses me  
a little.


Zitat von Martin Weiss <martin.weiss1@gmx.de>:

> <>
>
>
> How do you mean that? The example that Kit provided gives the same results?
> Did you get something else for your special dataset?
>
>
>
> HTH
> Martin
>
>
> -----Ursprüngliche Nachricht-----
> Von: owner-statalist@hsphsun2.harvard.edu
> [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von
> lschoele@rumms.uni-mannheim.de
> Gesendet: Dienstag, 21. April 2009 16:10
> An: statalist@hsphsun2.harvard.edu
> Betreff: re: AW: st: AW: beta coefficients for interaction terms
>
> I tried it out and got different figures for the beta coefficient.
> Thats why I asked that question.
> It should give me the same figures, right?
>
> Zitat von Christopher Baum <baum@bc.edu>:
>
> > <>
> > Why don't you just try it out?
> >
> > sysuse auto, clear
> > egen shead = std(headroom)
> > egen slength = std(length)
> > egen smpg = std(mpg)
> > gen ia2 = shead*slength
> > egen sia2 = std(ia2)
> > reg smpg shead slength sia2
> > reg mpg headroom length ia2, beta
> >
> > Kit Baum   |   Boston College Economics and 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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