Suppose customers arrive at a checkout counter according to a Poisson distri- bution at an average rate of seven per hour.

(a) What is the probability that exactly three customers arrive in a given two hour period?

(b) What is the probability that a total of four customers arrive between 1:00-2:00 pm and 3:00-4:00 pm?

(c) Show that the moment generating function for a Poisson random variable with parameterism(t) =e^(*(e^t)1)).