THX
Yao Zhu Department of Urology Fudan University Shanghai Cancer Center Shanghai, China 2010/6/4 Frank E Harrell Jr <f.harr...@vanderbilt.edu> > On 06/03/2010 11:32 AM, Joris Meys wrote: > >> You're right, it is the same. using I() won't work for the same reason >> sqrt >> don't, so : >> >> x2<- x^2 >>> lrm(y~x+x2) >>> >> >> Thx for the correction. >> Cheers >> Joris >> >> On Thu, Jun 3, 2010 at 6:14 PM, Bert Gunter<gunter.ber...@gene.com> >> wrote: >> >> Below. -- Bert >>> >>> Bert Gunter >>> Genentech Nonclinical Biostatistics >>> -------------------------------------- >>> But you wrote linear+ square. Don't you mean: >>> lrm(Y~x+x^2) >>> >>> --- I believe this is the same as lrm(Y ~ x). >>> You must protect the x^2 via >>> >>> lrm(Y ~ x + I(x^2)) >>> >> > But don't use that construct. Use lrm(Y ~ pol(x, 2)) > > Frank > > >>> ------------------------------------------ >>> >>> -- >>> >> Joris Meys >> Statistical Consultant >> >> Ghent University >> Faculty of Bioscience Engineering >> Department of Applied mathematics, biometrics and process control >> >> Coupure Links 653 >> B-9000 Gent >> > > > -- > Frank E Harrell Jr Professor and Chairman 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. > [[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 and provide commented, minimal, self-contained, reproducible code.
