Pitfall Traps

or a scene dramatic. An effective economist chooses the type of graph that best suits the purpose at hand. In this appendix we discuss how economists use graphs to study the mathematical relationships among variables. We also discuss some of the pitfalls that can arise in the use of graphical methods. G R A P H S O F A S I N G L E VA R I A B L E Three common graphs are shown in Figure 2A-1. The pie chart in panel (a) shows how total income in the United States is divided among…