On Tue, 1 Jan 2008, zhijie zhang wrote: > Dear all, > I have two variables, y and x. It seems that the relationship between them > is Piecewise Linear Functions. The cutpoint is 20. That is, when x<20, there > is a linear relationship between y and x; while x>=20, there is another > different linear relationship between them. > How can i specify their relationships in R correctly? > # glm(y~I(x<20)+I(x>=20),family = binomial, data = point) something like > this?
Try this: > library(splines) > fit <- glm( y ~ bs( x, deg=1, knots=20 ), family=binomial) HTH, Chuck > Thanks a lot. > > -- > With Kind Regards, > > oooO::::::::: > (..)::::::::: > :\.(:::Oooo:: > ::\_)::(..):: > :::::::)./::: > ::::::(_/:::: > ::::::::::::: > [***********************************************************************] > Zhi Jie,Zhang ,PHD > Tel:+86-21-54237149 > Dept. of Epidemiology,School of Public Health,Fudan University > Address:No. 138 Yi Xue Yuan Road,Shanghai,China > Postcode:200032 > Email:[EMAIL PROTECTED] > Website: www.statABC.com > [***********************************************************************] > oooO::::::::: > (..)::::::::: > :\.(:::Oooo:: > ::\_)::(..):: > :::::::)./::: > ::::::(_/:::: > ::::::::::::: > > [[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. > Charles C. Berry (858) 534-2098 Dept of Family/Preventive Medicine E mailto:[EMAIL PROTECTED] UC San Diego http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901 ______________________________________________ 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.
