試題詳解

308. A life insurance policy pays 1000 upon the death of a policyholder provided that the policyholder survives at least one year but less than five years after purchasing the policy.

Let X denote the number of years that a policyholder survives after purchasing the policy with the following probabilities:

  Calculate the standard deviation of the payment made under this policy.
(A) 218
(B) 430
(C) 480
(D) 495
(E) 500