Message-ID: <39B6DDB9048D0F4DAD42CB26AAFF0AFA076EBB@usctmx1106.merck.com>
Date: 2005-05-03T13:43:52Z
From: Liaw, Andy
Subject: Step wise regression
> From: Frank E Harrell Jr
>
> walmir-rodrigues wrote:
> > Dear Fellows,
> >
> > How can I do to proced a step wise regression in R, if it??s
> possible ?
> >
> > Thanks,
> >
> > Walmir
>
> Here is an easy approach that will yield results only slightly less
> valid than one actually using the response variable:
>
> x <- data.frame(x1,x2,x3,x4,..., other potential predictors)
> x[,sample(ncol(x))]
Hmm... Shouldn't that be something like:
x[, sample(ncol(x), ceiling(ncol(x) * runif(1)))]
?
Cheers,
Andy
> :-) -Frank
>
>
> --
> Frank E Harrell Jr Professor and Chair School of Medicine
> Department of Biostatistics
> Vanderbilt University
>
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