David Airey wrote: > While I defer to Frank as far as expertise goes, not having access to > his paper, I googled, and I just read that this kind of model is not > possible when there are a lack of ties for ranks in the data, and adds > an intercept for every rank in the data set. So while interpretation > doesn't get more difficult with additional ranks, unlike the > multinonimal model, Frank's suggestion would not fly for continuous > data that was transformed to ranks, as opposed to data collected as > ordered categories, where it would be preferable.
That is incorrect, except for the part about needing one intercept per unique value of Y, less one. This only presents a RAM and execution time problem. Sometimes I put continuous data into 100 quantile groups to make this fast. SAS JMP (after I suggested this to them in 1982) handles an arbitrarily high number of unique Y values as they made use of a patterned covariance matrix, which I didn't in lrm. So the PO model is a competitor of ordinary regression. A new option in predict.lrm makes it easy to get the predicted mean in this situation. Frank > > On Jan 23, 2008, at 10:52 AM, Frank E Harrell Jr wrote: > >> David Airey wrote: >>>> We need a two-way non-parametric ANOVA in order to analysis >>>> properly some ecological data, do you know any reference in R? or >>>> how to do it? Thank you very much All the best diana >>>> >>> A couple more references here are below. I liked the Scheirer >>> reference. >>> /* >>> Scheirer CJ, Ray WS, Hare N (1976) The analysis of ranked data >>> derived >>> from completely randomized factorial designs. Biometrics 32:429-434 >>> Groggel DJ, Skillings JH (1986) Distribution-free tests for main >>> effects >>> in multifactor designs. American Statistician 40:99-102 >>> */ >> My guess is that those are a bit out of date, especially the first >> one, when compared to the PO model. >> Cheers >> Frank >> >>> ______________________________________________ >>> 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 >>> and provide commented, minimal, self-contained, reproducible code. >> >> -- >> Frank E Harrell Jr Professor and Chair School of Medicine >> Department of Biostatistics Vanderbilt University > > ______________________________________________ > 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 > and provide commented, minimal, self-contained, reproducible code. > -- Frank E Harrell Jr Professor and Chair School of Medicine Department of Biostatistics Vanderbilt University ______________________________________________ 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 and provide commented, minimal, self-contained, reproducible code.
