(Ensure all work is shown) A survey conducted by a research team was set to investigate how years of education, tenure in current employment, and age, are related to annual income. A sample of 20 employees is selected and the Excel Regression output is provided: SUMMARY OUTPUT Regression Statistics Multiple R 0.94292564 R Square D.889 108762 Adjusted R Square 0.868316655 Standard Error 18812.28607 Observations 20 ANOVA 5S MS F Regression 3 77777 151335054.3 77777 Residual 16 56624337 77:777 Total 19 510629500 Coefficients Standard Error t Stat Intercept -64936.92607 26451.1321 -2.454977195 Education (No. of years) 4760.891103 1683.259323 2.828376495 Length of tenure (No. of years) 6788.273439 1242.676274 5.462624161 Age (No. of years) 595,7488449 682.6522618 D.872697387 a) Write the population regression line. b) Test the validity of the model at 99.5%