A student used multiple regression analysis to study how family spending (y) is influenced by income (x1), family size (x2), and additionsto savings(x3). The variables y, x1, and x3 are measured in thousands of dollars. The following results were obtained. ANOVA df SS Regression 3 45.9634 Residual 11 2.6218 Total Coefficients Standard Error Intercept 0.0136 x1 0.7992 0.074 x2 0.2280 0.190 x3 -0.5796 0.920 a. Write out the estimated regression equation for the relationship between the variables. (1 mark) b. Compute coefficient of determination. What can you say about the strength of this relationship? (3 marks) c. Carry out a test to determine whether y is significantly related to the independent variables. Use a 5% level of significance. (3 marks) d. Carry out a test to see if x3 and y are significantly related. Use a 5% level of significance. (3 marks) S