Exercise 6.9.5 Consider the model yi = 0 + 1xi + ei , ei s i.i.d. N(0,

Exercise 6.9.5 Consider the model yi = β0 + β1xi + ei , ei s i.i.d. N(0, σ2), i = 1, 2, 3, . . . , n. If the xi s are restricted to be in the closed interval [−10, 15], determine how to choose the xi s to minimize

(a) Var( ˆ β0).

(b) Var( ˆ β1).

(c) How would the choice of the xi s change if they were restricted to the closed interval [−10, 10]?