A. Introduction 1. At what point are changes in marginal product of special interest? 2. What are the stages of production based on? B. STAGE I: Increasing Returns 1. What is the criterion for determining how long total output will rise? 2. When should companies start hiring? C. STAGE II: Diminishing Returns 1. What happens to the rate of increase in total production during this stage? 2. What is the principle of diminishing returns? D. STAGE III: Negative Returns 1. What happens to marginal product during this stage? 2. What happens to total plant output during this stage? 3. What effect does the stage have on hiring