Andrew Clegg <andrew.clegg <at> gmail.com> writes: > > ... If I want to demonstrate that a non-linear curve fits > better than an exponential, what's the best measure for that? Given > that neither of nls() or optim() provide R-squared.
To supplement Karl's comment, try Douglas Bates' (author of nls) comments on the matter http://www.ens.gu.edu.au/ROBERTK/R/HELP/00B/0399.HTML Short summary: * ... "the lack of automatic ANOVA, R^2 and adj. R^2 from nls is a feature, not a bug :-)" * My best advice regarding R^2 statistics with nonlinear models is, as Nancy Reagan suggested, "Just say no." Dieter ______________________________________________ [email protected] 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.
