Supply in A Noncompetitive Market

1 What factors allow a firm to have monopoly profits?
2 Give one example in health care markets for each of the following market structure: (a) Perfect competition, (b) monopolistic competition, (c) oligopoly, (d) monopoly, (e) monopsony.
3 Compare the degree of market concentration for the following three regions by calculating the Herfindahl-Hirschman Index. Note that there are two units of the Index: (from 0 to 1 vs from 0 to 10000). If the range is from 0 to 10,000, the HHI is calculated by the percentage of the market share. If the range is from 0 to 1, we calculate it by the fraction of the market share. For example, there is a market that Company A shares 0.3 (which is 30%) and Company B shares 0.7(70%), the HHI is either 0.3x0.3 + 0.7x0.7 = 0.09+0.49= 0.58, or 30x30 + 70x70 = 5800.