Draw a normal probability distribution

gistfile1.r

mean=132; sd=13
lb=105; ub=159

x <- seq(-4,4,length=100)*sd + mean
hx <- dnorm(x,mean,sd)

plot(x, hx, type="n", xlab="Duration (days)", ylab="",
  main="Duration Probability Distribution", axes=FALSE)

i <- x >= lb & x <= ub
lines(x, hx)
polygon(c(lb,x[i],ub), c(0,hx[i],0), col="red", density=5)

area <- pnorm(ub, mean, sd) - pnorm(lb, mean, sd)
result <- paste("P(",lb,"< Duration <",ub,") =",
   signif(area, digits=3), "  mean = ",mean)
mtext(result,3)
axis(1, at=seq(40, 180, 20), pos=0)