Hi r-help-boun...@r-project.org napsal dne 07.06.2010 14:28:58:
> Dear list, > > I am getting weired with fitting data with a 1/x-polynomial. Suggest I have > the following data: > > x <- c(1,2,3,4,5,6,7) > y <- c(100,20,4,2,1,.3,.1) > > I may fit this with a linear model > > fit1 = lm(y ~ I(x)) fit1 = lm(y ~ x) is enough > > Getting plot out of this model I applied > library(polynom) > pol1 = polynomial(fit1$coefficients) > f1 = as.function(pol1) > > plot(x,y) > lines(x, f1(x), col = 2) why not plot(x,y) lines(x, fitted(fit)) > > Clearly, this model appears insufficient. Therefore I intended to aplly > fit2 = lm(y ~ I(1/x)) > pol2 = polynomial(fit2$coefficients) > f2 = as.function(pol2) > lines(x, f2(x), col = 3) The same applies here fit3 = lm(y ~ I(1/x^3)) lines(x, fitted(fit3)) seems to give quite reasonable output. Regards Petr > > as this would be much more pleasant. However, the second model does not work > at all. > > > Does anyone know about how to correctly fit an x^-1-polynomial to my data > cloud? > > > Many thanks in advance, > > > behelfsadresse > > [[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. ______________________________________________ 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.