2. To explain what determines the price of air conditioners, B.T. Ratchford obtained the following regression results based on a sample of 19 air conditioners: 'Y} = 68.236 + 0.023X2i + 19.729X3i + 7.653X4i Se = (0.05) (8.992) (3.082) R2 = 0.84 Where Y: price in dollars X2 = BTU rating of air conditioner X3 = energy efficiency ratio X4 = number of settings Se = standard errors of the estimate (a) Interpret the regression results. (b) Do the results make economic sense? (c) At 5% level of significance, test the hypothesis that BTU rating has no effect on the price of an air conditioner versus that it has a positive effect. (d) Would you accept the hypothesis that the three explanatory variables explain a substantial variation in the prices of air conditioners? Show clearly your calculations