Regression analysis is a statistical tool that utilizes the relation between
two or more quantitative variables so that one variable (dependent variable)
can be predicted from the others (independent variables). For example,
if one knows the relationship between advertising
expenditures and sales, one can predict sales by regression analysis once
the level of advertising expenditures has been set. In this chapter, we
specifically consider the case when a single independent variable is used
for predicting the dependent variable and the dependent variable and
the independent variable are linearly related.