example of each. 2. The estimated market demand for good X is Q =70 - 3.5P - 0.6M + 4P, where Q is the estimated number of units of good X demanded, P is the price of the good, M is income, and P, is the price of related good Z. (All parameter estimates are statistically significant at the 1 percent level.) a. Is X a normal or an inferior good? Explain. b. Are X and Z substitutes or complements? Explain. c. At P = 10, M = 30, and P, = 6, compute estimates for the price (E), income (Ey), and cross-price elasticities (E, xz)