Suppose an industry is composed of 10 firms. Each firm's share of total sales in the industry is 10 percent. If two of the firms merge, then the four-firm concentration ratio in the industry is

Shortage of a good occurs if: a. the price of the good is higher than the equilibrium price

b. the government imposes a restriction on the consumption of the good. c. buyers want to buy more than sellers want to sell. d. buyers want to buy less than sellers want to sell.

The theory of education that states firms use educational attainment as a way of sorting between high-ability and low-ability workers is called