[R] regression by groups

Chuck Cleland ccleland at optonline.net
Wed Oct 10 02:08:37 CEST 2007

Jiong Zhang, PhD wrote:
> Hi All,
> I want to run regression (lm) on my dependant variable by gender and race. How do I integrate the "by" function in lm?
> thanks.

  Here is an example using the iris data:

by(iris, iris$Species, function(x){
summary(lm(Sepal.Length ~ Sepal.Width +
                          Petal.Length +
                          Petal.Width, data=x))})

> jiong
>  The email message (and any attachments) is for the sole...{{dropped:11}}
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Chuck Cleland, Ph.D.
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