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Re: st: Categorical variable in regression
From
Petya Alexandrova <[email protected]>
To
[email protected]
Subject
Re: st: Categorical variable in regression
Date
Wed, 23 Jan 2013 13:32:30 +0200 (EET)
In a regression with dummy variables one category is always omitted because it is the reference category.
You can modify which category to be used as a reference group.
Petya
>-------- Оригинално писмо --------
>От: John Ataguba [email protected]
>Относно: st: Categorical variable in regression
>До: Statalist statalist mailing <[email protected]>
>Изпратено на: Сряда, 2013, Януари 23 13:22:09 EET
> Dear Statalist members
>
>
> I have a problem trying to let Stata display coefficients for all the categories of a categorical variable in a regression.
>
> Consider the example below:
>
> **********************************************
> clear
> set obs 200
> set seed 12345
> gen region = 1+int((4-1+1)*runiform())
> gen y = 10+(56-10)*runiform()
> xi: reg y i.region, noconst noomit
> **********************************************
>
> I expect Stata to display the coefficients for all the four categories of the categorical variable named "region". However, Stata still omits one category. Is there something I am doing wrong?
>
> I am running Stata 12.1 (SE) on Windows 7 platform. I also tried this in Stata 11.2 (IC) on Windows 7 platform and I obtained the same result.
>
> I will appreciate your assistance.
>
> Regards
>
> Jon
>
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