Hello Listserv: I am requesting your help in interpreting the results of quadratic terms in multiple regression.
I've hypothesized a curvilinear relationship (inverted U) between a dependent and an independent variable. To test this hypothesis, I centered the independent variable, squared it and entered it along with the linear term in the regression model. I got different results with independent variables and I have tried to summarize them in the following questions: 1. Is it necessary to have a positive linear term and a negative quadratic (squared term) to support the curvilinear relationship? 2. Is it necessary to have a significant linear term too? How you interpret the result when both the linear and quadratic terms are significant compared to when the quadratic term is significant while the linear term is not? 3. How do you interpret when both the linear and quadratic terms have negative beta coefficients? I would greatly appreciate your time and help. Happy holidays. Thanking you. Nabin Baral
