From: Berton Gunter <gunter.berton_at_gene.com>

Date: Wed 07 Dec 2005 - 08:27:17 EST

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Wed Dec 07 08:53:23 2005

Date: Wed 07 Dec 2005 - 08:27:17 EST

But note: There are (almost?) no situations in R where the dummy variables
coding is needed. The coding is (almost?) always handled properly by the
modeling functions themselves.

Question: Can someone provide a "straightforward" example where the dummy variable coding **is** explicitly needed?

- Bert Gunter Genentech Non-Clinical Statistics South San Francisco, CA

"The business of the statistician is to catalyze the scientific learning process." - George E. P. Box

> -----Original Message-----

*> From: r-help-bounces@stat.math.ethz.ch
**> [mailto:r-help-bounces@stat.math.ethz.ch] On Behalf Of Liaw, Andy
**> Sent: Tuesday, December 06, 2005 12:30 PM
**> To: 'Charles H. Franklin'; r-help@stat.math.ethz.ch
**> Subject: Re: [R] Matrix of dummy variables from a factor
**>
**> See ?model.matrix.
**>
**> HTH,
**> Andy
**>
**> From: Charles H. Franklin
**> >
**> > What is a simple way to convert a factor into a matrix of
**> > dummy variables?
**> >
**> > fm<-lm(y~f)
**> >
**> > where f is a factor takes care of this in the estimation.
**> I'd like to
**> > save the result of expanding f into a matrix for later use.
**> >
**> > Thanks.
**> >
**> > Charles
**> >
**> > --
**> >
**> >
**> > Charles H. Franklin
**> > Professor, Political Science
**> > University of Wisconsin, Madison
**> > franklin@polisci.wisc.edu
**> > chfrankl@wisc.edu
**> > 608-263-2022 (voice)
**> > 608-265-2663 (fax)
**> >
**> > ______________________________________________
**> > R-help@stat.math.ethz.ch mailing list
**> > https://stat.ethz.ch/mailman/listinfo/r-help
**> > PLEASE do read the posting guide!
**> > http://www.R-project.org/posting-guide.html
**> >
**> >
**>
**> ______________________________________________
**> R-help@stat.math.ethz.ch mailing list
**> https://stat.ethz.ch/mailman/listinfo/r-help
**> PLEASE do read the posting guide!
**> http://www.R-project.org/posting-guide.html
*

>

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Wed Dec 07 08:53:23 2005

*
This archive was generated by hypermail 2.1.8
: Fri 03 Mar 2006 - 03:41:30 EST
*