ABSTRACT
Until now we have assumed that the relationship between the dependent and independent variables could be explained on the basis of a linear model. However, the real world is not linear. There are many business and economic relationships that are non-linear (or curvilinear). In fact, most economic functions do not fit a linear model. Cost curves, production functions, earnings functions, measures of profitability, revenues, sales, and most other business-related measures are all best explained with non-linear models.
