For the data on VOTE (Y) and TVEXP (X) in Problem 5 in Chapter 5, it was found that the straight-line model was adequate. Using the accompanying computer output for quadratic regression, do the following:
a. Plot the fitted straight-line model and the fitted quadratic model on the scatter diagram for the data of this problem.
b. Determine the change in R2 in going from a degree 1 to a degree 2 model.
c. Test for the significance of the addition of the X2 term to the model.
d. Assess whether the results in parts (a) through (c) contradict your earlier conclusion about the adequacy of fit of the straight-line model.

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Straight-line regression of Y on X R-Square Adj R-Sq 0.9101 Root MSE Dependent Mean Coeff Var 3.33177 45.71000 7 28894 0.9051 PARAMETER ESTIMATES Parameter Standard Variable DF Estimate Intercept Error tValue Pr> I 3.30974 2.17407 0.66 0.5196 1769 0087180 001 718 13.50 <0001 Quadratic regression of Y on X Type I Sum of DF Squares R-Square F Value Pr> F Regression Linear Quadratic Total Model 1 2023.205063 2.450153 2 2025.655215 0.9101 0.0011 09112 87.24 0001 174.27 0001 0.21 0,6518 Sum of Squares Residual Lack of Fit Pure Error Total Error DF 12 166.802785 5 30.560000 Mean SquareF ValuePr>F 227 01874 13.900232 6.112000 11 609576 17 197 362785 Standard Error Parameter DF t Value Pr> 1 9.656782 16.636082 1 0.750772 0.931996 081 0.4316 1 0.005746 0.012508 Intercept 0.58 0.5692 046 06518