Hi: Borrowing from this thread, courtesy of Brian Diggs: http://groups.google.com/group/ggplot2/browse_thread/thread/478f9e61d41b4678/ed323c497db61156?lnk=gst&q=stat_function#ed323c497db61156
...here's a small reproducible example: ddf <- data.frame(x = 1:10, y = 0.4 + 0.6 * (1:10) + rnorm(10)) # Find the linear model coefficients lmc <- coef(lm(y ~ x, data = ddf)) # Create a function to produce the fitted line lmeq <- function(x) lmc[1] + lmc[2] * x # Construct the ggplot() and use stat_function(): ggplot(ddf, aes(x = x, y = y)) + geom_point() + stat_function(fun = lmeq, colour = 'red', size = 1) HTH, Dennis On Thu, Nov 10, 2011 at 10:47 AM, Curiouslearn <curiousle...@gmail.com> wrote: > Hi All, > > I have a scatter plot produced using ggplot2 and I want to add the > regression line to this scatter plot. I suppose I can use > geom_smooth() to do this, but for the sake of learning ( I am new both > to R and ggplot2), I want to try and add it as a function (something > that curve() does in the standard R plotting). I did some search and > found that stat_function() can be used for this. But somehow it is not > working. The following is my code. Can you please tell me where I am > going wrong and what the correct code would be: > > reg1 <- lm(kid_score ~ mom_hs, data=iqdata) > > scatter <- ggplot() + geom_point(data=iqdata, > > aes(x=as.factor(mom_hs), y=kid_score) ) > + xlab("Mother's High School Status") > + ylab("Children's Test Score") > + stat_function(fun=function(x) > coef(reg1)[1] + coef(reg1)[2] * x) > > I understand that you probably do not have the data I am using (I am > trying this out from Gelman Hill's book on Multilevel models). But I > was hoping you may be able to point out the error without the data. > > Thanks for your help. > > ______________________________________________ > 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.