[R] Categorical Variables and glm()

2009-01-23 Thread Stephen Collins 
When including categorical variables in a regression, the default in R is 
to set the first level as the base.  Is there an option to specify a 
different level as the base? 

Regards, 
 
Stephen Collins, MPP | Analyst
Health  Benefits | Aon Consulting

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Re: [R] Categorical Variables and glm()

2009-01-23 Thread Marc Schwartz 
on 01/23/2009 11:10 AM Stephen Collins wrote:
 When including categorical variables in a regression, the default in R is 
 to set the first level as the base.  Is there an option to specify a 
 different level as the base? 

See ?relevel and the See Also's listed therein.

HTH,

Marc Schwartz

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Re: [R] Categorical Variables and glm()

2009-01-23 Thread Daniel Malter 
Hi,

contrasts(yourvariablename)=contr.treatment(levels(yourvariablename),base=3)


3 is the number of the category that you want to be your baseline. Replace
accordingly.

Cheers,
Daniel


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Betreff: [R] Categorical Variables and glm()

When including categorical variables in a regression, the default in R is to
set the first level as the base.  Is there an option to specify a different
level as the base? 

Regards, 
 
Stephen Collins, MPP | Analyst
Health  Benefits | Aon Consulting

[[alternative HTML version deleted]]

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and provide commented, minimal, self-contained, reproducible code.

__
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.