> 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.
Have a look to the package segmented if you don't know exactly the breakpoint and you are interested in estimating it, all the best, vito 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. > > ______________________________________________ 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.
