4. (Statistical Inference) Given the following model, M = 131 + 132x+ 1632? + 52'- I have collected data and computed the following moment matrix with M = [1, x, z, y] for you: 120 150 80 450 150 300 250 2000 80 250 600 1200 450 2000 1200 25000 M'M= (a) How many observations have I collected? What are the average values for each variable, that is 37, :3, and :2? (b) Using OLS formula to compute the coefcient estimates, [31, 32, and ,03. What is the residual variance, the variance-covariance matrix of estimates, and the R2 for this regression? [Hint: 6'6 2 Y'Y B'X'Y] (c) Test the hypothesis of 1) ,83 = 3 and 2)Bl + 102 = 0 separately. ((1) Test the hypotheses of ,63 = -3 and [31 + ,82 = 0 simultaneously. Comparing (c) and (d), what do you conclude