Airline passengers arrive randomly and independently at the passenger-screening facility at a major international alrport. The mean arrival rate is 7 passengers per minute. a. Compute the probability of no arrivals in a one-minute period (to 6 decimals). b. Compute the probability that three or fewer passengers arrive in a one-minute period (to 4 decimals). c. Compute the probability of no arrivals in a 15 -second period (to 4 decimals). d. Compute the probability of at least one arrival in a 15 -second period (to 4 decimals)