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Re: st: back transform coefficients


From   Nikolaos Pandis <npandis@yahoo.com>
To   "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu>
Subject   Re: st: back transform coefficients
Date   Fri, 18 Nov 2011 03:48:59 -0800 (PST)

Dear Maarten,
 
Great, many thanks for the help.
I assume from your posting that after I run the command I need to follow an extra step in order to get the coeffs in the origninal scale.
Would you be able to be more specific on how to accomplish this.
 
Many thanks,
 
Nick


________________________________
From: Maarten Buis <maartenlbuis@gmail.com>
To: statalist@hsphsun2.harvard.edu 
Sent: Friday, November 18, 2011 11:52 AM
Subject: Re: st: back transform coefficients

On Fri, Nov 18, 2011 at 10:05 AM, Nikolaos Pandis wrote:
> I am running linear regression with 3 continous and 1 2-level categorical independent variables.
> The continuous outcome is normally distributed when transformed into sqrt(dep_var).
> I was wondering how I would be able to back transform the produced coefficients and CIs for interpretation.

I would not use -regress- to estimate such model, but -glm- with the
-link(power .5)- option. That way you are modeling the square root
transformed mean of your dependent variable rather than the mean of
your square root transformed dependent variable. This makes the
backtransform much easier, just use -predict-, -margins-, etc.

Hope this helps,
Maarten

--------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany


http://www.maartenbuis.nl
--------------------------

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