MicroeconomicUNCERTAINTYANDINFORMATION文件材料.ppt

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To view a full-screen figure during a class, click the red “expand” button. To return to the previous slide, click the red “shrink” button. To advance to the next slide, click anywhere on the full screen figure. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * The table gives the quantity of ice cream consumed at different prices as the temperature varies. Graphing Relationships Among More Than Two Variables To plot this relationship we hold the temperature at 70°F. At $2.75 a scoop, 10 gallons are consumed. Graphing Relationships Among More Than Two Variables We can also plot this relationship by holding the temperature constant at 90°F. At $2.75 a scoop, 20 gallons are consumed. Graphing Relationships Among More Than Two Variables When temperature is constant at 70°F and the price of ice cream changes, there is a movement along the blue curve. Graphing Relationships Among More Than Two Variables When temperature is constant at 90°F and the price of ice cream changes, there is a movement along the red curve. Graphing Relationships Among More Than Two Variables When Other Things Change The temperature is held constant along each curve, but in reality the temperature can change. Graphing Relationships Among More Than Two Variables When the temperature rises from 70°F to 90°F, the curve showing the relationship shifts rightward from the blue curve to the red curve. Graphing Relationships Among More Than Two Variables 2 THE ECONOMIC PROBLEM Why does food cost much more today than it did a few years ago? One reason is that we now use part of our corn crop to produce ethanol, a clean biofuel substitute for gasoline. Another reason is that drought in some parts of the world has decreased global grain production. We use an economic model—the production possibilities frontier—to learn why ethanol production and drought have increased the cost of producing food.