Engineering economy analyses are often made for both the most and least favorable combinations of forecasted future conditions. This procedure has two major weaknesses. First, the two solutions usually indicate that contradictory courses of action should be followed. When this occurs, the engineeringeconomic study has failed to provide the management of a business with a quantitative aid and mathematical method for evaluating data and arriving at sound decisions. Second, that method of analysis is unrealistic because it emphasizes the extreme possibilities rather than some intermediate situation which is more likely to occur.