R help - Jan 2009 - termplot

I have used glm and stepAIC to choose a best model.  I can use termplot to
assess the contribution of each explanatory variable in the glm.  However
the final model after running stepAIC includes interaction terms, and when I
do termplot I get "Error in `[.data.frame`(mf, , i) : undefined columns
selected".  I also see the termplot detail saying "Nothing sensible
happens
for interaction terms."   

Is it possilbe to determine explanatory power of final set of variables when
interactions are included?  
 
Thanks

- Bob

Dear Bob,

Take a look at the effects package, described in
<http://www.jstatsoft.org/v08/i15/paper>.

I hope this helps,
 John

------------------------------
John Fox, Professor
Department of Sociology
McMaster University
Hamilton, Ontario, Canada
web: socserv.mcmaster.ca/jfox

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at
r-project.org]
On
> Behalf Of Robert Michael Inman
> Sent: January-19-09 8:17 AM
> To: r-help at r-project.org
> Subject: [R] termplot
> 
> I have used glm and stepAIC to choose a best model.  I can use termplot to
> assess the contribution of each explanatory variable in the glm.  However
> the final model after running stepAIC includes interaction terms, and when
I
> do termplot I get "Error in `[.data.frame`(mf, , i) : undefined
columns
> selected".  I also see the termplot detail saying "Nothing
sensible
happens
> for interaction terms."
> 
> Is it possilbe to determine explanatory power of final set of variables
when
> interactions are included?
> 
> Thanks
> 
> - Bob
> 
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