Financial advising (a)  Starting with the model in Table 4, add both Employment and Annual Payroll to the model. Does  adding this pair improve the fit of the model by a ...

Financial advising

(a)  Starting with the model in Table 4, add both Employment and Annual Payroll to the model. Does  adding this pair improve the fit of the model by a  statistically significant amount?

(b) Instead of adding the pair as in (a), add the ratio AnnualPayroll/Employment (average payroll salary). Does adding this ratio produce a statistically significant improvement?

(c) Explain your preference among the original model and these two models that add variable.