All work must be shown step by step to be correct.

a.)

A college found that 20% of its students withdraw without completing the introductory statistics course. Assume that 20 students registered for the course.

1.Compute the probability that 2 or fewer will withdraw.

2.Compute the probability that exactly 4 will withdraw.

3.Compute the probability that more than 3 will withdraw.

4.Compute the expected number of withdrawals.

b.)

Passengers arrive randomly and independently at the passenger-screening facility at a major international airport.The mean arrival rate is 10 passengers per minute.

1.Compute the probability of no arrivals in a one-minute period.

2.Compute the probability that three or fewer passengers arrive in a one-minute period.

3.Compute the probability of no arrivals in a 15-second period.

4.Compute the probability of at least one arrival in a 15-second period.