During lunch time, customers arrive at Bob's Drugs according to a Poisson distribution with (lambda) = 4 per minute.
a. During a one-minute interval, determine the following probabilities: (1) no arrivals; (2) one arrival; (3) two arrivals; and, (4) three or more arrivals.
b. What is the probability of two arrivals in a two-minute period?
c. What is the probability that no more than 30 seconds elapses between arrivals?