15-1. The following output is associated with a multiple regression model with three independent variables: Table 1 af SS MS F p-value Regression 3 16,646.091 5,548.697 5.328 0.007 Residual 21 21,871.669 1,041.508 Total 24 38,517.760 Table 2 Coefficients Standard Error t Stat p-value Intercept 87.790 25.468 B.447 0.002 X1 -0.970 0.586 -1.650.113 X2 0.002 0.001 3.133 0.005 X3 -8.723 7.495 -1.160.258 4 Table 3 Lower 95% Upper 95% Lower 90% Upper 90% Intercept 34.827 140.753 43.966 131.613 -2.189 0.248 -1.979 0.038 0.001 0.004 0.001 0.004 -24.311 6.864 -21.621 4.174 a. What is the regression model associated with these data? b. Is the model statistically significant? c. How much of the variation in the dependent variable can be explained by the model? d. Are all of the independent variables in the model significant? If not, which are not and how can you tell? e. How much of a change in the dependent variable will be associated with a one-unit change in x2? In x3? f. Do any of the 95% confidence interval estimates of the slope coefficients contain zero? If so, what does this indicate