曼昆经济学原理第5版微观P第五章.pptVIP

* These calculations are based on the example shown a few slides back: points A and B on the website demand curve. * In essence, the textbook says “Here are the determinants of elasticity. The first one is availability of close substitutes. Here’s an example….” That’s great for a textbook. For teaching, I’ve found a different approach to be far more effective: having students deduce the general lessons from specific examples they can figure out using common sense. This is the approach on the next few slides. Also, see notes on the next slide for a good suggestion. * Suggestion: For each of these examples, display the slide title (which lists the two goods) and the first two lines of text (which ask which good experiences the biggest drop in demand in response to a 20% price increase). Give your students a quiet minute to formulate their answers. Then, ask for volunteers. * You might need to clarify the nature of this thought experiment. Here, we look at two alternate scenarios. In the first, the price of blue jeans (and no other clothing) rises by 20%, and we observe the percentage decrease in quantity of blue jeans demanded. In the second scenario, the price of all clothing rises by 20%, and we observe the percentage decrease in demand for all clothing. * This slide is a convenience for your students, and replicates a similar table from the text.  If you’re pressed for time, it is probably safe to omit this slide from your presentation. * Economists classify demand curves according to their elasticity. The next 5 slides present the five different classifications, from least to most elastic. * If Q doesn’t change, then the percentage change in Q equals zero, and thus elasticity equals zero. It is hard to think of a good for which the price elasticity of demand is literally zero. Take insulin, for example. A sufficiently large price increase would probably reduce demand for insulin a little, particularly among people with very