Customers come to a self-service gas station at the rate of 20 per hour. Their arrivals are modeled by a Binomial counting process.

(a) How many frames per hour should we choose, and what should be the length of each frame if the probability of an arrival during each frame is to be 0.05?

(b) With this frames, find the expected value and standard deviation of the time between arrivals at the gas station.