Using a statistics program, consider again the relationship between the population and ozone level of U. S. cities that you analyzed in Exercise 37.

In exercise

a) Give a 90% confidence interval for the approximate in-crease in ozone level associated with each additional million city inhabitants.
b) For the cities studied, the mean population was 1.7 million people. The population of Boston is approximately 0.6 million people. Predict the mean ozone level for cities of that size with an interval in which you have 90% confidence.

Dependent variable s 0zone R-squared-84.4% s= 5.454 with 16-2=14 df SE (Coeff) 2.395 1.910 Variable Intercept Pop Coeff 18.892 6.650