FW: st: Plotting several linear associations in one graph for comparison

[Amal Khanolkar <Amal.Khanolkar@ki.se>]

Hello all,

Regarding my previous question: plotting multiple linear regressions stratified by a particular variable on the same graph. I received some example syntax from Maarten but I was unable to understand the details.

Does anybody else have any ideas on how twoway line plot can be exploited for my prupose?

My original Q:

 - I've run some very basic and simple linear regression models to analyse associations between standardized birth weight and blood pressure, adjusting for confounders like birth year, current age, BMI, height etc.
>
> - The associations between birth weight and blood pressure are stratified by ethnicity (12 ethnic goups - thus 12 separate linear regression models). I see that the association between birth weight and blood pressure does differ in the various ethnic goups.
>
> - I would now like to plot the above associations in a single graph using different colours for the various ethnic groups for comparison.

Thanks!

Amal.
________________________________________
From: Amal Khanolkar
Sent: 13 July 2012 15:22
To: statalist@hsphsun2.harvard.edu
Subject: RE: st: Plotting several linear associations in one graph for comparison

Hi Maarten,

Thanks for your example.

Just wondering what the 'replace' commands are doing specifically? I guess it's not important for me.

Ideally, I ran my regressions stratifying by race, (if race==1 and so on) - should I also predict yhat separately for each racial group as well?

Thanks,

/Amal.
________________________________________
From: owner-statalist@hsphsun2.harvard.edu [owner-statalist@hsphsun2.harvard.edu] on behalf of Maarten Buis [maartenlbuis@gmail.com]
Sent: 13 July 2012 15:10
To: statalist@hsphsun2.harvard.edu
Subject: Re: st: Plotting several linear associations in one graph for comparison

On Fri, Jul 13, 2012 at 2:42 PM, Amal Khanolkar wrote:
> - I've run some very basic and simple linear regression models to analyse associations between standardized birth weight and blood pressure, adjusting for confounders like birth year, current age, BMI, height etc.
>
> - The associations between birth weight and blood pressure are stratified by ethnicity (12 ethnic goups - thus 12 separate linear regression models). I see that the association between birth weight and blood pressure does differ in the various ethnic goups.
>
> - I would now like to plot the above associations in a single graph using different colours for the various ethnic groups for comparison.

*---------------- begin example ----------------
sysuse nlsw88, clear
reg wage i.race##c.grade i.union hours ttl_exp
preserve
replace union = 1
replace hours = 40
replace ttl_exp = 15
bys race grade : keep if _n == 1
predict yhat
separate yhat, by(race)
twoway line yhat1 yhat2 yhat3 grade
restore
*--------------- end example -------------------
(For more on examples I sent to the Statalist see:
http://www.maartenbuis.nl/example_faq )

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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