The economist who, in his presidential address to the American Economic Association in 1967, attacked the idea of a permanent downward-sloping Phillips curve was

If an industry has 25 firms that collectively have $150 million in total sales and the top four firms in this industry account for $90 million in sales, what is the concentration ratio of the top four firms in this industry?

A) 42 percent B) 60 percent C) 70 percent D) 80 percent

If a study by medical researchers finds that eating brown rice causes weight loss while eating white rice causes weight gain, then we likely would see

a. an increase in demand for brown rice and a decrease in demand for white rice. b. a decrease in demand for brown rice and an increase in demand for white rice. c. an increase in demand for both brown and white rice. d. no change in demand for either type of rice because weight loss is not a determinant of demand.