試題詳解

158. The number of days an employee is sick each month is modeled by a Poisson distribution with mean 1. The numbers of sick days in different months are mutually independent.

Calculate the probability that an employee is sick more than two days in a three-month period.
(A) 0.199
(B) 0.224
(C) 0.423
(D) 0.577
(E) 0.801