On Jan 12, 2013, at 5:04 PM, Ahmed Attia wrote: > So what is the best method to test the goodness of fit in nonlinear > models?
Did you read the citation offered? -- David. > > On Sat, Jan 12, 2013 at 4:34 PM, David Winsemius <dwinsem...@comcast.net > > wrote: > > On Jan 12, 2013, at 3:30 PM, Ahmed Attia wrote: > > Please help getting the R squared value in asymptotic regression model > > I use the code below > > model1<-nls(GN1~SSasymp (nrate,a,b,c), data = data.1 ) > > and R produced the modell coefficients without the R squared value? > > What makes you think there should be an R^2 value? > > From the archives: > https://stat.ethz.ch/pipermail/r-help/2002-July/023461.html > > http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2892436/ > > From the background section to that article: > > "Although it is known now for some time that R2 is an inadequate > measure for nonlinear regression, many scientists and also reviewers > insist on it being supplied in papers dealing with nonlinear data > analysis. Several initial and older descriptions for R2 being of no > avail in nonlinear fitting had pointed out this issue but have > probably fallen into oblivion [2-8]. This observation might be due > to differences in the mathematical background of trained > statisticians and biochemists/pharmacologists who often apply > statistical methods but lack detailed statistical insight." > > -- > > David Winsemius, MD > Alameda, CA, USA > > > > > -- > Ahmed M. Attia > > > Research Assistant > Dept. Of Soil&Crop Sciences > Texas A&M University > ahmed.at...@ag.tamu.edu > Cell phone: 001-979-248-5215 > David Winsemius, MD Alameda, CA, USA [[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.
