3.15 McDonald and Ayers [1978] present data from an early study that examined the possible link between air pollution and mortality. Table B.15 summarizes the data. The response MORT is the total age-adjusted mortality from all causes, in deaths per 100,000 population. The regressor PRECIP is the mean annual precipitation (in inches), EDUC is the median number of school years completed for persons of age 25 years or older, NONWHITE is the percent- age of the 1960 population that is nonwhite, NOX is the relative pollution potential of oxides of nitrogen, and SO is the relative pollution potential of sulfur dioxide. "Relative pollution potential" is the product of the tons emitted per day per square kilometer and a factor correcting the SMSA dimensions and exposure. a. Fit a multiple linear regression model relating the mortality rate to these regressors. b. Test for significance of regression. What conclusions can you draw? c. Use t tests to assess the contribution of each regressor to the model. Discuss your findings. d. Calculate R and Raj for this model. e. Find a 95% CI for the regression coefficient for SO. TABLE B.15 Air Pollution and Mortality Data Mort Precip 790.73 13.00 823.76 28.00 839.71 844.05 857.62 860.10 861.44 861.83 City San Jose, CA Wichita, KS San Diego, CA Lancaster, PA Minneapolis, MN Dallas, TX Miami, FL Los Angeles, CA 10.00 43.00 25.00 35.00 60.00 11.00 Educ 12.20 12.10 12.10 9.50 12.10 11.80 11.50 12.10 Nonwhite 3.00 7.50 5.90 2.90 3.00 14.80 11.50 7.80 Nox 32.00 2.00 66.00 7.00 11.00 1.00 1.00 319.00 SO2 3.00 1.00 20.00 32.00 26.00 1.00 1.00 130.00