(2)单一的管制不行;可以采取回报率管制
只要所定的回报率稍微高于Pr,都能给厂商带来利润,厂商就能相机抉择。
(3)这里可以回答很多经济学原理。
**以下仅作参考**(曼昆提出的经济学十大原理)
Principle #1: People face tradeoffs
Principle #2: The cost of something is what you give up to get it
Principle #3: Rational people think at the margin
Principle #4: People respond to incentives
Principle #5: Trade can make everyone better off
Principle #6: Markets are usually a good way to organize economic activity
Principle #7: Governments can sometimes improve market outcomes
Principle #8: A country’s standard of living depends on its ability to produce goods and services
Principle #9: Prices rise when the government prints too much money
Principle #10: Society faces a short-run tradeoff between inflation and unemployment