試題詳解

複選題
9. Cars arrive at a car wash service randomly and independently. The probability of an arrival is the same for any interval of equal length. The mean arrival rate is 4 cars per 10 minutes. Which of the following is/are correct?
(A) The probability that less than 2 cars will arrive during any given 10 minutes of operation is 0.0916；
(B) The probability that 5 or more cars will arrive during any given 10 minutes of operation is 0.7815；
(C) The probability that more than 6 cars will arrive during any given 10 minutes of operation is 0.1107；
(D) The probability that exact 9 cars will arrive during any given 10 minutes of operation is 0.0550；
(E) The variance of the arrival rate per 10 minutes is 4.