I am having trouble replicating this in R.

(a) Create a data frame (or a tibble) named df with 500 rows and 4 variables: a, b, c and, d. Each variable should contain data generated randomly from a different type of distribution (e.g. rnorm generates normally distributed data randomly: there are several other similar commands available that you need to lookup) The data frame will look something like the following example 1.2 0.4 0.1 4.9 0.9 1.3 0.9-0.7