The following are the design matrix , response vector Y, and (a'a)-1 for a multiple linear regression model. 1.33 -0.33 -0.50 Y = -1 00 A -1 09 01 (xx) = -0.33 0.67 0.00 -0.50 0.00 0.25 (a) Calculate the least squares estimates of the model y. = Bo + Bici,1 + Bar;2 + 6; for i = 1, . . . .n. (b) Calculate an unbiased estimate for the variance of the random errors. (c) Calculate a 95% confidence interval for B2. (d) Briefly explain an implication of the O's in the (a'a) ' matrix