In a second-order polynomial regression model, the regression coefficient, B2, will be positive if the parabola opens downward and negative when the parabola opens upward.

Question

Quizplus · Accepted Answer

The sign of B2 in a second-order polynomial regression model indicates the direction of the curvature of the parabola, not the direction it opens. A positive B2 means the parabola opens upward, and a negative B2 means it opens downward.

In a Second-Order Polynomial Regression Model, the Regression Coefficient, B2