Message-ID: <20050916123844.KCAL28424.tomts25-srv.bellnexxia.net@JohnDesktop8300>
Date: 2005-09-16T12:38:45Z
From: John Fox
Subject: plot(<lm>): new behavior in R-2.2.0 alpha
In-Reply-To: <17194.30238.436418.752419@stat.math.ethz.ch>
Dear Werner,
> -----Original Message-----
> From: Werner Stahel [mailto:stahel at stat.math.ethz.ch]
> Sent: Friday, September 16, 2005 2:37 AM
> To: Martin Maechler
> Cc: R-devel at stat.math.ethz.ch; John Maindonald; Werner
> Stahel; John Fox
> Subject: Re: plot(<lm>): new behavior in R-2.2.0 alpha
>
. . .
>
> For most plots, I like to see a smoother along with the points.
> I suggest to add the option to include smoothers, not only as
> an argument to plot.lm, but even as an option().
I agree that smoothers are useful.
. . .
> I clearly support to add either vif or -- equivalent and more
> intuitive to me -- R^2_j, the coefficient of determination of
> lm(X_j~.) However
> -- this should be included in the coefficient table of print.lm
> -- this adds another useless and misleading quantity for
> dummy x-variables It is therefore quite a different question.
>
Generalized variance inflation factors (as computed by the vif function in
car) apply to sets of related regressors in a term, such as dummy
regressors.
. . .
Regards,
John