7. (a) Fit a multiple linear regression (MLR) of Isav on age, nchild, line, grad and hols, and

report the regression results.

(b) Which of the regressors are individually significant at the 10% level? And at the 5%

level?

(c) Carry out a test of the joint significance of the variables age, nchild, grad and hols.

Which model do you prefer the SLR model in the previous question, or the MLR

model in this question?

(d) Carry out a RESET test in the MLR model - is there evidence of functional form mis-

specification?

(e) Carry out a test for heteroskedasticity in the MLR model - is there evidence of het-

eroskedasticity?