Random Variables

Random numbers

• r for random numner

• d for density

• p for cumulative distribution

• q for quantile function

More about functions is here.

The random numbers are not actually random. You can reproduce them by setting seed.

> set.seed(1)
> rnorm(5)
[1] -0.6264538  0.1836433 -0.8356286  1.5952808  0.3295078

> set.seed(1)
> rnorm(5)
[1] -0.6264538  0.1836433 -0.8356286  1.5952808  0.3295078

Sampling

> set.seed(1)

> sample(1:10, 4)
 [1] 3 4 5 7
> sample(letters, 4)
 [1] "f" "w" "y" "p"
> sample(letters, replace=T)
 [1] "q" "b" "f" "e" "r" "j" "u" "m" "s" "z" "j" "u" "y" "f" "q" "d" "g" "k" "a" "j" "w" "i" "m" "p" "m" "e"

With replace set to true, the values can repeate.