Find the indicated probabilities using the geometric distribution, the Poisson distribution, or the binomial distribution. Then determine if the events are unusual. If convenient, use the appropriate probability table or technology to find the probabilities.

The mean number of oil tankers at a port city is

12

per day. The port has facilities to handle up to

15

oil tankers in a day. Find the probability that on a given day, (a)

twelve

oil tankers will arrive, (b) at most three oil tankers will arrive, and (c) too many oil tankers will arrive.

(a)

P(twelve

oil tankers will

arrive)equals

0.1144(Round to four decimal places as needed.)

(b) P(at most three oil tankers will

arive)equals

0.0023(Round to four decimal places as needed.)

(c) P(too many oil tankers will

arrive)equals

0.1556(Round to four decimal places as needed.)

A.

The event in part (a) is unusual.

B.

The event in part (b) is unusual.

This is the correct answer.

C.

The event in part (c) is unusual.

D.

None of the events are unusual.