Shading a kernel density plot between two points.

Question

I frequently use kernel density plots to illustrate distributions. These are easy and fast to create in R like so:

set.seed(1)
draws <- rnorm(100)^2
dens          


        

Answer 1

With the polygon() function, see its help page and I believe we had similar questions here too.

You need to find the index of the quantile values to get the actual (x,y) pairs.

Edit: Here you go:

x1 <- min(which(dens$x >= q75))  
x2 <- max(which(dens$x <  q95))
with(dens, polygon(x=c(x[c(x1,x1:x2,x2)]), y= c(0, y[x1:x2], 0), col="gray"))

Output (added by JDL)