To Test Whether or Not the Population Regression Function Is

Multiple Choice

To test whether or not the population regression function is linear rather than a polynomial of order r,

A) check whether the regression R² for the polynomial regression is higher than that of the linear regression.
B) compare the TSS from both regressions.
C) look at the pattern of the coefficients: if they change from positive to negative to positive, etc., then the polynomial regression should be used.
D) use the test of (r-1) restrictions using the F-statistic.