試題詳解

225. The loss L due to a boat accident is exponentially distributed.

Boat insurance policy A covers up to 1 unit for each loss. Boat insurance policy B covers up to 2 units for each loss.

The probability that a loss is fully covered under policy B is 1.9 times the probability that it is fully covered under policy A.

Calculate the variance of L.
(A) 0.1
(B) 0.4
(C) 2.4
(D) 9.5
(E) 90.1