Chapter 7: Handling Non-Linear Relationship Using Quadratic Effect Modeling (QEM)
1. Non-linear Relationship Explained Experienced researchers would agree that variables do not always hold a linear relationship as in a straight line (Hay & Morris, 1991; Eisenbeiss, CorneliEen, Backhaus, & Hoyer, 2014). For example, in the field of marketing, advertising activities and sales revenue often hold a non-linear, quadratic relationship.48 Consumers may be eager