interpreting results of regression using ordinal predictors in R
On Jan 2, 2013, at 10:09 PM, Bert Gunter wrote:
Below ... -- Bert On Wed, Jan 2, 2013 at 9:54 PM, David Winsemius <dwinsemius at comcast.net
wrote:
... Search on "orthogonal polynomials". Yes, but this does not explain what these have to do with ordered factors and contrasts in a linear model. That information is contained in "An Introduction to R," the tutorial that ships with R and which the OP should have perused before posting. Detailed explanation beyond that is too technical for here, I would say.
The material in "Intro to R" is, I think all will agree, rather sketchy. I think this strategy will be more productive: http://lmgtfy.com/?q=%22orthogonal+polynomials%22+linear+models Second link was: www.stats.ox.ac.uk/pub/StatMeth/Linear2_04.pdf
David. > > -- Bert > > > > > Note that my question is not on lm (I think), but rather on how lm > outputs the results of regressions involving ordered predictors. Some > references would be great. > > Please post responses to this mailing list. > > > As always. > > Thanks very much again for all your help! > > > -- > > > David Winsemius, MD > Alameda, CA, USA > > ______________________________________________ > R-help at 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 > and provide commented, minimal, self-contained, reproducible code. > > > > -- > > Bert Gunter > Genentech Nonclinical Biostatistics > > Internal Contact Info: > Phone: 467-7374 > Website: > http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm > David Winsemius, MD Alameda, CA, USA