Probability Distributions for Discrete Random Variables

A life insurance policy pays 1000 upon the death of a policyholder provided that the policyholder su at least one year but less than five years after purchasing the policy. Let X denote the number of yea policyholder survives after purchasing the policy with the following probabilities:

X 1 2 3 4 5
P(x). 0.05 0.12 0.21 0.33 0.48

Calculate the mean, the variance and the standard deviation of the payment made under this polic