30.

a. Recalling the de nition of s2 for a single rv X, write a formula that would be appropriate for computing the variance of a function h(X, Y) of two random variables. (Hint: Remember that variance is just a special expected value.)

b. Use this formula to compute the variance of the recorded score h(X, Y) [ max(X, Y)] in part (b)

of Exercise 18.