Dear Jonathan, An alternative is to use the raw argument to poly(), possibly after centering the predictor. This probably will work OK as long as the degree of the polynomial isn't high.
I hope this helps, John -------------------------------- John Fox Department of Sociology McMaster University Hamilton, Ontario Canada L8S 4M4 905-525-9140x23604 http://socserv.mcmaster.ca/jfox -------------------------------- > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of > Jonathan Greenberg > Sent: Wednesday, November 01, 2006 9:39 PM > To: R-help > Subject: [R] poly() question > > Besides the primary citation, "Kennedy, W. J. Jr and Gentle, > J. E. (1980) Statistical Computing Marcel Dekker." (which is > $300 and my library doesn't have it), is there any other > documentation on how to take a poly() object and predict "by > hand" new data? E.g. What do those coefficients actually > mean ("The orthogonal polynomial is summarized by the > coefficients, which can be used to evaluate it via the > three-term recursion...")? We created a GLM model with a > poly() term and I'm trying to apply this model in another > program (grass gis via mapcalc) without requiring the direct > link with R if at all possible. We'd like to avoid making a > lookup table if at all possible. Thanks! > > --j > > -- > Jonathan A. Greenberg, PhD > NRC Research Associate > NASA Ames Research Center > MS 242-4 > Moffett Field, CA 94035-1000 > Office: 650-604-5896 > Cell: 415-794-5043 > AIM: jgrn307 > MSN: [EMAIL PROTECTED] > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
