set.seed(1)                             # Ensure a reproducible stream

(s1 <- rnorm(5))

(s2 <- rnorm(5))

set.seed(1)
(s2 <- rnorm(5))

all.equal(s1, s2)

mean(rexp(1e6, rate = 1))

mean(rexp(1e6, rate = 0.5))

mean(rexp(1e6, rate = 2))

var(rexp(1e6, rate = 1))

var(rexp(1e6, rate = 0.5))

var(rexp(1e6, rate = 2))

mean(rexp(9, rate = 1))

str(mns9 <- replicate(10^5, mean(rexp(9, rate = 1))))

mean(mns9)

sd(mns9)

library(ggplot2)
qplot(mns9, geom="density", main="Means of samples of size 9 from an exponential dist.")

qplot(sample=mns9, main="Means of samples of size 9 from an exponential dist.")