What null hypothesis are you trying to test? There is a standard null for linear models that makes sense in a large number of cases, but what the null is for non-linear regression is not obvious (and the coefficient = 0 may not even be possibly, let alone interesting). If you can state what your null hypothesis is then there are ways to get p-values, but easier is to just compute confidence intervals for the parameter of interest and see if the null value is in the interval.
-- 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-bounces@r- > project.org] On Behalf Of Tatiana Donnay > Sent: Thursday, September 15, 2011 6:41 AM > To: r-h...@stat.math.ethz.ch > Subject: [R] Nonlinear regression question > > Hello, > > If I understand good, I can't have p-value for the nls model. > > I have 2 vectors. And I'am doing > > model <- nls(crf ~a*(1-exp(-x/b)) + c, data= d, > start = list(a=1, b=3, c=0)) > > and I want to know If my result is significat, if I can't have p-value, > how can I know it? > > Thank you > ______________________________________________ > 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.
