Wilson, Andrew wrote: > Probably a very simple query: > > When I try to plot a curve from a fitted polynomial, it comes out rather > jagged, not smooth like fitted curves in other stats software. Is there > a way of getting a smooth curve in R? > > What I'm doing at the moment (for the sake of example) is: > >> x <- c(1,2,3,4,5,6,7,8,9,10) > >> y <- c(10,9,8,7,6,6.5,7,8,9,10) > >> b <- data.frame(cbind(x,y)) > >> w <- gls(y ~ I(x)+I(x^2),correlation=corARMA(p=1),method="ML",data=b) > >> plot(predict(w),type="l")
predict() predicts at all locations in x and you are drawing straight lines between these points. Hence you need to predict in another resolution, e.g.: dat <- data.frame(x = seq(1, 10, by = 0.1)) plot(predict(w, newdata = dat), type="l") Uwe Ligges > Many thanks, > > Andrew Wilson > > ______________________________________________ > R-help@stat.math.ethz.ch 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@stat.math.ethz.ch 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.
