polynomial contrasts with the scores argument should do what you want.

?contr.poly

As an example:


contr.poly(4, c(1,2,4,8))
diff(contr.poly(4, c(1,2,4,8))[,1])



On Wed, Feb 2, 2011 at 2:40 PM, Asan Ramzan <asanramzan@yahoo.com> wrote:

> Hello [R]-help
>
> I am trying to find
> > a package where you can do ANOVA based trend analysis on grouped data
> > using orthogonal polynomial contrasts coefficients, for unequally
> > spaced factor levels. The closest hit I've had is from this web site:
> >(
> http://webcache.googleusercontent.com/search?q=cache:xN4K_KGuYGcJ:www.datavis.ca/sasmac/orpoly.html+Orthogonal+polynomial
> >l
>
> but I cannot find this package or anything like it.
>
>
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
> and provide commented, minimal, self-contained, reproducible code.
>

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