Natural splines (nsin the splines package rcs in the Hmisc or Design package) are linear outside of the range of the knots. You could use those and just specify the knots to be within the portion that you want to allow to be non-linear.
Hope this helps, -- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare greg.s...@imail.org 801.408.8111 > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r- > project.org] On Behalf Of serbring > Sent: Saturday, July 25, 2009 3:29 AM > To: r-help@r-project.org > Subject: [R] spline regression > > > i have a trend that it is linear at first and then it has a particular > trend. > There is a mathematic model, but it describes only the linear part. I > have > tried to use a spline regressione, but i have obtained a particular fit > trend that it is unreal. Can i create a spline regression that it is of > a > unitary degree only at first? > -- > View this message in context: http://www.nabble.com/spline-regression- > tp24656274p24656274.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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.
