In: Statistics and Probability
Assume that customer arrivals at a barber shop are random and independent of one another, and the number of customer arrivals at a barber shop and the time until the next customer arrives is independent.
(a) In city A, on average, 3 customers arrive at a barber shop every hour. Using an appropriate probability distribution,
(i) find the probability that at least 5 customers arrive at a barber shop every hour.
(ii) A sample of 25 barber shops in city A was obtained. Find the probability that at least 3 barber shops were visited by at least 5 customers.
(iii) A customer has just arrived in a barber shop. Find the probability that the time, until the next customer arrives will be at most 2 hours (from now).