8.1 β0, β2, β3, and β4 determine the intercept while the other parameters determine the slope.
8.3 a. Let
= .42 + 1.77x1
which is not significant.
c. There is a problem with normality and a pattern to the residuals.
= 33.6 − .0457x1
. No, the t
= −.22 with p
= 0.824 which is not significant.
= 42.92 − .117x1
. There is a significant interaction between engine displacement and the type of transmission. When the transmission is automatic, = (42.92 − 13.46) ...