02像经济学家一样思考解析.ppt

* * Here, we are using “workers” for the more general “resources,” to keep things simple and consistent with the previous examples. * * The bow-shaped PPF is more realistic. However, the linear PPF is simpler to work with, and we can learn a lot about how the economy works using the linear PPF. In Chapter 3, we will use a linear PPF to show how trade can make two countries (or two individuals) better off. Note: In the “Problems and Applications” at the end of the chapter, problem 4 asks students to construct a PPF for an economy with three different workers (Larry, Moe, and Curly), each with a different opportunity cost. The PPF ends up having three line segments (one for each worker), which--very roughly--approximates a bow-shape. After students work through and understand this problem, it should not be hard for them to understand the following: the more different kinds of workers (or, more generally, resources) there are, the closer the PPF will resemble a smooth bow shape. In an actual economy like the U.S., there are millions of different workers with different opportunity costs, so a smooth bow-shaped PPF is a nearly perfect approximation to the actual PPF. * * * * * CHAPTER 2 THINKING LIKE AN ECONOMIST A Why the PPF Might Be Bow-Shaped Mountain Bikes Beer At A, opp. cost of mtn bikes is low. At point A, most workers are producing beer, even those that are better suited to buildingmountain bikes. So, do not have to give up much beer to get more bikes. CHAPTER 2 THINKING LIKE AN ECONOMIST B Why the PPF Might Be Bow-Shaped Mountain Bikes Beer At B, opp. cost of mtn bikes is high. At B, most workers are producing bikes. The few left in beer are the best brewers. Producing more bikes would require shifting some of the best brewers away from beer production, would cause a big drop in beer output. 为什么生产可能性边界可能是曲线 因此，当不同的工人有不同的技能，多生产1单位物品的机会成本也不同，这使生产可能性边界为曲线 当经济中存在一些其他资源，或者机会成本不同的资源混合时，生产可能性边界也可能是曲线（例如，不同类型的土地有不同的用处） CHAPTER 2 THINKI