[R] Fitting arbitrary curve to 1D data with error bars

[Suzen, Mehmet]

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)