applied statistics

3

3. Let Z and W be two random variables such that cov(Z, W) = -4, var(Z) = 10 and var(W ) = 5. Find var (Z - W). (a) 23 (b) 7.5 ( c ) 7 (d) 11 (e) 154. Which of the following random variables is the the z- score for the random variable W where E(W ) = -u and var (W) = n2. (a) (W - M) /(o/ vn) ( b) (W + 1 )/ Vn (c) (W - M) / Vn ( d) ( W + u) (e) ( W - M) / o