微观经济学需求与供给剖析.ppt

* P2 P1 石油数量 0 石油价格 需求 S 2 S 1 (a) 短期石油市场 P2 P1 石油数量 0 石油价格 需求 S 2 S 1 (b) 长期石油市场 2. ..引起 价格大 幅度上升 在长期中，当供给 与需求富有弹性时，供 给移动… 2. ..引起 价格小 幅度上升 在短期中，当供给和需求缺乏 弹性时，供给移动… Figure 5-9 OPEC 为什么不能保持石油的高价格？ 弹性及其应用 * 应用：禁毒增加还是减少了与毒品相关的犯罪 使用毒品的一个不利影响是犯罪：吸毒上瘾的人往往会有暴力犯罪，以得到吸毒所需要的钱 我们比较两种旨在减少吸毒的政策，并观察它们对与毒品相关的犯罪的影响 为简化起见，我们假定与毒品相关的犯罪的美元价值等于购买毒品的总支出 由于吸毒成瘾，非法毒品的需求是缺乏弹性的 0 弹性及其应用 * D1 政策 1: 禁毒 0 毒品价格 毒品数量 S1 S2 P1 Q1 P2 Q2 禁毒减少了毒品供给 由于毒品的需求是缺乏弹性的，毒品价格提高的比例会大于毒品使用减少的比例 结果：在毒品上的总支出和与毒品相关的犯罪都会增加 与毒品相关的犯罪的新价值 与毒品相关的犯罪的最初价值 弹性及其应用 * 政策 2: 教育 0 毒品价格 毒品数量 D1 S P1 Q1 D2 P2 Q2 教育减少对毒品的需求. 价格与需求量都下降 结果：在毒品上的总支出和与毒品相关的犯罪都减少了 与毒品相关的犯罪的最初价值 与毒品相关的犯罪的新价值 * * 76 8 * In the textbook, this application appears near the end of the chapter, and you can easily move these slides to the end if you wish to teach things in the same order as the book. However, I encourage you to consider teaching this application right here - immediately after the section on price elasticity of demand. It is safe to do so, as this application only requires knowledge of price elasticity of demand. Also, putting the application here breaks up what would otherwise be a very long section of theory with a real-world example that most students find very interesting. Knowing elasticity helps us understand what might otherwise be a counter-intuitive result (that drug interdiction increases drug-related crime rather than reducing it). * By the time all elements have appeared on the screen, the slide will look kind of busy. I think this is okay, because the elements appear on the screen one by one, so students have time to absorb each one before the next one appears. However, if you’d rather strip the slide down a bit, here’s a suggestion: in “Normal” view (which one uses to edit slides), you can delete the boxes that represent the initial and new values of drug-related crime, and the accompanying captions. Then, when presenting this slide in class, simply point out (with your mouse cursor, a laser pointer, or ev