The number of telephone calls that arrive at a phone exchange is often modeled as a Poisson

random variable. Assume that on the average there are 10 calls per hour.

(a) What is the probability that there are exactly 5 calls in one hour?

(b) What is the probability that there are 3 or less calls in one hour?

(c) What is the probability that there are exactly 15 calls in two hours?

(d) What is the probability that there are exactly 5 calls in 30 minutes?

define the equation used and write the R code of the solution