x <- rnorm(100,10,1) sqrtx <- sqrt(x) y <- rbinom(100,1,0.5) lrm(y~x+sqrtx)
works. What's the problem? But you wrote linear+ square. Don't you mean: lrm(Y~x+x^2) Cheers On Thu, Jun 3, 2010 at 6:34 AM, zhu yao <mailzhu...@gmail.com> wrote: > Dear r users > > I have a question in coding continuous variables in logistic regression. > > When "rcs" is used in transforming variables, sometime it gives implausible > associations with the outcome although the model x2 is high. > > So what's your tips and tricks in coding continuous variables. > > P.S. How to code variables as linear+square in the formula such as lrm. > lrm(y~x+sqrt(x)) can't work. > > Many thanks. > > Yao Zhu. > > [[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. > -- Joris Meys Statistical Consultant Ghent University Faculty of Bioscience Engineering Department of Applied mathematics, biometrics and process control Coupure Links 653 B-9000 Gent tel : +32 9 264 59 87 joris.m...@ugent.be ------------------------------- Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php [[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.
