An R package is simply a collection of functions. Each function does a specific task. Write a $($single$)$ function that computes $-$

a$.$ Arithmetic mean,

b$.$ Standard deviation, and

c$.$ Range. Range is the difference between the maximum and minimum values of a variable

for any variable of an $R$ data.frame$().$ Implement this function on the airquality data available with baseR. Show your code and output.