(True/False) Because polynomials are smooth functions, it is permissible to extrapolate slightly beyond the range of the independent variable when fitting quadratic models. You fit a full regression...

(True/False) Because polynomials are smooth functions, it is permissible to extrapolate slightly beyond the range of the independent variable when fitting quadratic models.

You fit a full regression model with five independent variables, obtaining an SSE with 40 df. Then you fit a reduced model that has only three of the independent variables, but now you obtain an SSE with 46 df. Does this make sense? What is the most likely explanation? What should you do?