Re: [R] A regression problem using dummy variables

From: Moshe Olshansky <m_olshansky_at_yahoo.com>
Date: Tue, 01 Jul 2008 17:23:48 -0700 (PDT)


Do you have a reason to treat all 3 levels together and not have a separate regression for each level?

> From: rlearner309 <unixunix99_at_gmail.com>
> Subject: [R] A regression problem using dummy variables
> To: r-help@r-project.org
> Received: Tuesday, 1 July, 2008, 11:38 PM
> This is actually more like a Statistics problem:
> I have a dataset with two dummy variables controlling three
> levels. The
> problem is, one level does not have many observations
> compared with other
> two levels (a couple of data points compared with 1000+
> points on other
> levels). When I run the regression, the result is bad. I
> have unbalanced
> SE and VIF. Does this kind of problem also belong to
> "near sigularity"
> problem? Does it make any difference if I code the level
> that lacks data
> (0,0) in stead of (0,1)?
>
> thanks a lot!
> --
> View this message in context:
> http://www.nabble.com/A-regression-problem-using-dummy-variables-tp18214377p18214377.html
> Sent from the R help mailing list archive at Nabble.com.
>
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