On Tue, 15 May 2012 20:33:02 -0400, David Winsemius wrote > On May 15, 2012, at 8:08 PM, Francisco Mora Ardila wrote: > > > Hi all > > > > I have fitted a model usinf nls function to these data: > > > >> x > > [1] 1 0 0 4 3 5 12 10 12 100 100 100 > > > >> y > > [1] 1.281055090 1.563609934 0.001570796 2.291579783 0.841891853 > > [6] 6.553951324 14.243274230 14.519899320 15.066473610 21.728809880 > > [11] 18.553054450 23.722637370 > > > > The model fitted is: > > > > modellogis<-nls(y~SSlogis(x,a,b,c)) > > > > It runs OK. Then I calculate confidence intervals for the actual > > data using: > > > > dataci<-predict(as.lm(modellogis), interval = "confidence") > > > > BUt I don´t get smooth curves when plotting it, so I want to get > > other "confidence > > vectors" based on a new x vector by defining a new data to do > > predictions: > > > > x0 <- seq(0,15,1) > > dataci<-predict(as.lm(modellogis), newdata=data.frame(x=x0), > > interval = "confidence") > > > > BUt it does not work: > > I am really getting tired of seeing the phrase "doesn't work". And on > my machine it throws an error saying there is no as.lm function> This > seemes to give "smooth results:
Sorry for that "doesn't work". Also, I forgot to say function as.lm() is in tha package nls2, which also fit nls models. > > dataci<-predict(as.lm(modellogis), newdata=data.frame(x=x0), interval > = "confidence") > > And notice that this message is in ?predict.nls > > interval > "At present this argument is ignored. Yeah, that´s why I´m using nls2 package > > > I get the same initial confidence interval > > > > Any ideas on how to get tconfidence and prediction intervals using > > new X data on a > > previous model? > > > > Thanks > > > > Francisco > > > > > > > > ---------------------- > > Francisco Mora Ardila > > Estudiante de Doctorado > > Centro de Investigaciones en Ecosistemas > > Universidad Nacional Autónoma de México > > > > ______________________________________________ > > 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. > > David Winsemius, MD > West Hartford, CT ---------------------- Francisco Mora Ardila Estudiante de Doctorado Centro de Investigaciones en Ecosistemas Universidad Nacional Autónoma de México ______________________________________________ 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.