If you are after adding error bars in a scatter plot; one example is given below :
#some example data set.seed(42) df <- data.frame(x = rep(1:10,each=5), y = rnorm(50)) #calculate mean, min and max for each x-value library(plyr) df2 <- ddply(df,.(x),function(df) c(mean=mean(df$y),min=min(df$y),max=max(df$y))) #plot error bars library(Hmisc) with(df2,errbar(x,mean,max,min)) grid(nx=NA,ny=NULL) (From: http://stackoverflow.com/questions/13032777/scatter-plot-with-error-bars) ______________________________________________ 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.