[R] Linear Regression ?
Roland Rau
roland.rproject at gmail.com
Mon Jun 16 19:29:29 CEST 2008
Hi,
did you have a look at the manual "An Introduction to R"?
(http://cran.r-project.org/doc/manuals/R-intro.html).
Chapter "Statistical Models in R" should answer (most of) your questions
concerning linear regression.
kayj wrote:
>
> Also each x is a categorical variable with 4 categories so I have to
> introduce three variables for each x
>
If I understood correctly what you mean (-> coding of dummy variables),
this is not necessary in R. If you variable is a "factor", R does it for
you automatically. If you are unhappy with the choice of reference
category, please check:
?relevel
I hope this helps,
Roland
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