On Nov 9, 2012, at 12:52 PM, Jacob B. <jdbowen...@gmail.com> wrote: > Hello, > > I'm trying to fit a logistic curve to data but I'm having a hard time > discovering how. Every tutorial I've come across either assumes the > logistic curve has 0<y<1 or assumes I have multiple categories of data > > I simply have two vectors, a and b, of equal length with no missing > data, and I suspect they follow a logistic curve. > > The vectors are > > a<-c(39609, 39643, 39700, 39829, 39889, 39926, 40008, 40084, 40183, > 40276, 40297, 40336, 40422, 40471, 40565, 40700, 40731, 40820, 40971, > 41071, 41205) > > b<-c(0,10000000, 100000000, 500000000, 800000000, 1000000000, > 1500000000, 2000000000, 3000000000, 4000000000, 4500000000, > 5000000000, 6500000000, 7000000000, 10000000000, 14000000000, > 15000000000, 18000000000, 25000000000, 30000000000, 35000000000) > > How do I find the best-fit logistic curve for this data in R? > > - J
You might want to look at John Fox' appendix on non-linear models for some additional insights: http://socserv.mcmaster.ca/jfox/Books/Companion/appendix/Appendix-Nonlinear-Regression.pdf Regards, Marc Schwartz ______________________________________________ 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.
