An equation that describes how y is related to x and an error term ϵ
Testing for significance:
Coefficient of determination (r2) is a measure of the goodness of fit of the estimated regression equation.
However, even with a large value of r2, the estimated regression equation should not be used until further analysis of the appropriateness of the assumed model has been conducted.
An important step in determining whether the assumed model is appropriate involves testing for the significance of the relationship.
The tests of significance in regression analysis are based on the following assumptions about the error term ϵ