R help - Sep 2009 - Compare a group of line slopes

Hi, all,

I am thinking to compare a group of slopes from regression lines to see if
they are different overall, and then make specific comparisons between
groups. How can I achieve that in R?  I searched the archives and there are
only discussions about comparing two lines a time.  Thanks.

A sample data set is like the following. I would like to compare the
regression slopes between the five groups. Thanks for your help.

data<-data.frame(x=rep(1:10,5),y=rnorm(50),group=rep(1:5,each=10))

Jun Shen

	[[alternative HTML version deleted]]

The test that a slope differs by group is a test that the
variable*group interaction equals
zero (overall test). Maybe searching post-hoc comparisons in
regression will give you some
leads.

On Tue, Sep 15, 2009 at 10:57 AM, Jun Shen <jun.shen.ut at gmail.com>
wrote:
> Hi, all,
>
> I am thinking to compare a group of slopes from regression lines to see if
> they are different overall, and then make specific comparisons between
> groups. How can I achieve that in R? ?I searched the archives and there are
> only discussions about comparing two lines a time. ?Thanks.
>
> A sample data set is like the following. I would like to compare the
> regression slopes between the five groups. Thanks for your help.
>
> data<-data.frame(x=rep(1:10,5),y=rnorm(50),group=rep(1:5,each=10))
>
> Jun Shen
>
> ? ? ? ?[[alternative HTML version deleted]]
>
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