Perhaps you missed my statement that the
efficiency was about 20%. If you didn't and still
made this comment, ah well.
Hugo Hidalgo wrote:
>
> This is just an idea:
>
> Could it be that your predictors are intercorrelated, and you are just
> overfitting the model?
> Stepwise regression could allow this to happen if the predictors pass the
> t-test.
> See:
> Belsey,1991. Conditioning Diagnostics: Collinearity and Weak data in
> regression.
>
> Hugo
>
> Bob Wheeler wrote in message <[EMAIL PROTECTED]>...
> >His name is Chris Jordan, from "a manufacturing
> >company." Why he chooses to keep it secret is
> >anybody's guess, but of course it is rude.
> >
> >His problem is that he has calculated a response
> >using a mathematical formula that apparently is
> >well represented by a quadratic, and hence R^2 is
> >near unity -- the difference is likely due to
> >rounding. It is not a statistical problem. The
> >design, by the way, is not D-optimal, but rather
> >has an efficiency of about 20%.
> >
> >
> >Rich Ulrich wrote:
> >>
> >> (I am just addressing a single point.)
> >> On 30 Sep 2000 14:06:59 -0700, [EMAIL PROTECTED] (Donald Burrill)
> >> wrote:
> >>
> >> < concerning >
> >> > On Sat, 30 Sep 2000 [EMAIL PROTECTED] wrote:
> >> < snip, most >
> >> > > My adjusted R square is also very close to R Square.
> >>
> >> DB>
> >> > As is natural for R very close to 1.
> >>
> >> - but how close is "very close"? I don't think it can be,
> >> with 30/31 as the R-squared expected by chance.
> >>
> >> Using the adjusted R-squared formula in Cohen and Cohen,
> >> the distance from 1.0 will be 30 times as big as the observed,
> >> so that .9954 will be shrunk to .86. Assuming that you do start
> >> with the full number of variables in the equation, as is usually
> >> recommended. But you still get "a lot" of shrinkage by my
> >> book, even if you say the error is (say) only 10 times as
> >> big as the observed error of 0.0046.
> >>
> >> --
> >> Rich Ulrich, [EMAIL PROTECTED]
> >> http://www.pitt.edu/~wpilib/index.html
> >
> >--
> >Bob Wheeler --- (Reply to: [EMAIL PROTECTED])
> > ECHIP, Inc.
--
Bob Wheeler --- (Reply to: [EMAIL PROTECTED])
ECHIP, Inc.
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