--- Joseph Coveney <[email protected]> wrote:
>>
> In addition to what Tim Wade mentioned, consider
> using the same tactic that
> you would after ANOVA, viz., orthogonal polynomial
> contrasts and examining
> the linear component (first orthogonal polynomial
> contrast). You can do
> this manually with your dummy (indicator) variables
> using -lincom-, but it's
> easier to use one of the two user-written programs
> that help set this
> up: -xi3- and -desmat-.
>
>
Actually Richard Gates from Stata Corp in a private
email sugested the same thing. When I performed this
analysis, only the linear component was significant
with a p-value close to that produce by simply
including the the "un-dummy" term. So that is good. Is
there a reference for this orthogonal polynomial
approach?
Thank you,
Ricardo.
Ricardo Ovaldia, MS
Statistician
Oklahoma City, OK
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