A pair of dice is thrown. Let Z 1 be the number shown on the first die and Z 2 be the number shown on the second die. Let X = Z 1 + Z 2 and Y = Z 1 Z 2 . Find a. E ( Z 1 ) b. E ( Z 2 2 ) . C. E ( X ) . d. E ( Y ) . e. E ( X Y ) . f. E ( X 2 ) . g. E ( Y 2 ) ..