4. A cross-sectional data base of 10,000 persons who purchased Macintosh apples in 1989 was used to estimate the sample regression function: = 150 - 2.5pi, where q is the quantity of Macintosh apples demanded in 1989, and p is the price per dozen of these apples. If the average price per dozen paid by these persons was $8: (a) What is the predicted quantity demanded for 1989? (b) Using the answer from (a), what is the estimated price elasticity of demand for Macintosh apples? (c) What is estimated total spending on Macintosh apples when price is $5 (calculate the new for this answer). (d) Graph the demand curve for Macintosh apples implied by this function. Show that the elasticity of demand varies along this curve even though it is a straight line.