(b) Use matrix methods to obtain: i. (XX)-1 (a 3 by 3 matrix) ii. b = (XX)-1XTY (a 3 by 1 column-vector) iii. e (a 6 by 1 column-vector) iv. MSE (a scalar) v. se?(b) (a 3 by 3 matrix) [Sometimes this matrix is called s?(b)] vi. Y, when Xmi = 10, Xn2 = 30 (a scalar) vii. se?( Y, ) when Xml = 10, Xn2 = 30 (a scalar) [Hint: Observe that Xh = (1, 10, 30)?]