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Re: st: mean centering


From   David Hoaglin <dchoaglin@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: mean centering
Date   Sun, 20 Jan 2013 20:56:44 -0500

The QR decomposition is not a panacea.  If the matrix of predictor
variables is ill-conditioned enough, some loss of precision can still
result.  We might do well to regard centering as preventive medicine.

David Hoaglin

On Sun, Jan 20, 2013 at 7:01 PM, Jvverkuilen <jvverkuilen@gmail.com> wrote:
> Yes, from what I recall from scientific computing, the QR decomposition solves the numerical problems. It effectively centers and orthogonalizes the variables.
>
> Centering is really about interpretation now.
>
> --
> JVerkuilen, PhD
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