Re: [R] fractional factorial design in R

From: Berton Gunter <gunter.berton_at_gene.com>
Date: Tue 24 Jan 2006 - 06:28:45 EST


>
> At the moment, I am using an SPSS function (orthoplan) for my
> needs. It provides factorial design with only main effects
> (small orthogonal designs).
> Since SPSS is very expensive (in particular with this
> add-on), I would like to use R as for all my other projects
> and research activity.

Yes, you're right. For, say, a 3 x 5 design, one can do this in as few as 7 runs -- but only in general by some version of one-factor-at-a-time (OFAT) designs, which are inefficient. It is easy, via, say model.matrix() to write a general function to produce these. But I think it's a bad idea; more efiicient algorithmic designs are better, IMO, which is why I suggested AlgDesign. You and others are free to disagree, of course.

Cheers,
Bert

>
> Do you know any other way to produce these designs in R?
>
> Thanks in advance,
>
> Roberto Furlan
> University of Turin, Italy
>
>
>
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