4. A casualty insurance company has 1000 policyholders} each of whom may indepen- dently present a claim in the next month with probability 0.05. Assuming that the amounts of claims made are independent exponential random variables with mean $300 [i.e., A = 1/300). Estimate the probability that the total amount of claims next month exceeds $50,001] by generating 200 values of the total amount of claims and also estimate the variance of your estimator; Improve the estimate in Part (a) by the conditional espectatoa method (with the con- ditioning variable N = total number of claims made in the next month) and estimate the variance of the latter estimator