4. (Statistical Inference) Given the following model, \"92' = 51 + 132%- + 163%; + 6::- 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 g, :r, and z? (b) Using OLS formula to compute the coeicient estimates, 31, 5'2, and 33. What is the residual variance, the variancecovariance matrix of estimates, and the R2 for this regression? [Hintz e'e = Y'Y 'X'Y] (0) Test the hypothesis of 1) ,63 = 3 and 2W1 + g = 0 separately. (d) Test the hypotheses of [33 = 3 and 61 + g = 0 simultaneously. Comparing (c) and ((1), what do you conclude