You haven't said anything about the response. It
is obviously in the space spanned by the terms of
the model. It could be something simple as the
presence of exact replicates. (If it is truly
D-optimal and if you truly used all 27 terms, then
it must be a full factorial. Is it?)
[EMAIL PROTECTED] wrote:
>
> Hi,
>
> I constructed a D-optimal design for 6 continuous variables, each at
> three levels. I have 31 runs. My initial model includes, all the main
> effects, all interactions and polynomial terms. I was only able to
> remove 3 of the terms using step wise regression, My final model has an
> R square of 0.9954, which looks very artificial. My adjusted R square
> is also very close to R Square. Does anyone have any suggestion on what
> could have gone wrong or if there is a different analysis technique
> that I can use?
> I even did a lack of fit test, and the interaction terms and square
> terms were significant. I'll appreciate any help in this regard. Thanks
> for your help!
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.
--
Bob Wheeler --- (Reply to: [EMAIL PROTECTED])
ECHIP, Inc.
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