1. A market is considered unconcentrated if the Herfindahl-Hirschman Index (HHI) is below _______and is highly concentrated if the HHI is at least ______.
2. For a market with four firms, each with a 25 percent market share, the Herfindahl-Hirschman Index (HHI) is equal to ______.
3. Oligopolies occur for three reasons: (1) the government may limit the number of firms in a market by granting ______or limiting the number of ______; (2) large economies of______; (3) to get a foothold in the market, large expenditures on ______are required.
4. Although there are relatively small ______in the production of breakfast cereal, the market is an oligopoly because of the substantial investment in______ required to enter the market.