Question 16 A linear industry demand function of the form: Q = a + bP + cM + dPR, was estimated using regression analysis. The results of this estimation are as follows: DEPENDENT VARIABLE: R-SQUARE F-RATIO P-VALUE ON F OBSERVATIONS: 32 0.9419 151.32 0.0001 PARAMETER STANDARD VARIABLE ESTIMATE ERROR T-RATIO P-VALUE INTERCEPT 11408.600 2256.3200 5.06 0.0001 P -432.590 107.2700 -4.03 0.0004 M -0.089 0.0234 -3.78 0.0008 PR 126.350 71.7700 1.76 0.0892 The sign of d' implies that the commodity and related good are