第1讲 经与济学研究什么 .pptVIP

* * * * * * * * * * The success of a model is judged by its ability to predict. Help your student’s appreciate that no matter how appealing or “realistic looking” a model appears to be, it is useless if it fails to predict. And the converse, no matter how abstract or far removed from reality a model appears to be, if it predicts well, it is valuable. Milton Friedman’s pool hall example illustrates the point nicely. Imagine a physicist’s model that predicts where a carefully placed shot of a pool shark would go as he tries to sink the eight ball into the corner pocket. The model would be a complex, trigonometric equation involving tangents, cosigns and a plethora of Greek symbols that no ordinary person would even recognize as representing a pool shot. It wouldn’t depict what we see—a pool stick striking a pool cue on a rectangular patch of green felt. It wouldn’t even reflect the thought processes of the pool shark, who relies on years of experience and the right “touch.” But constructed correctly, this mathematical model would predict exactly where the cue ball would strike the eight ball, hit opposite the bank, and fall into the corner pocket. (You can invent analogous examples from any sport.) * * * * * The production possibility frontier (PPF) is the first economic model the students see. Your first challenge it to ensure that the students understand the mechanics of the model. You can provide some help in the classroom but you main goal must be to get the student working—to develop good work habits. Encourage them to work the end-of-chapter problems, study guide questions, and to work the Practice Problems in MyEconLab so that they are comfortable with the mechanics of this chapter. * Your second challenge is to help the students begin to use the PPF model and to start thinking like economists. Thinking about everyday events in terms of graphs and tables of numbers is hard for most students. You can help them to appreciate economic modes in general and the PPF