The Environmental Protection Agency is examining the relationship between the ozone level (in parts per million) and the population (in millions) of U.S. cities. Part of the regression analysis is shown, where the dependent variable is Ozone.
Dependent variable is: Ozone R squared = 84.4% s = 5.454 with 16 - 2 = 14 df
Variable Coefficient SE(Coeff)
a) We suspect that the greater the population of a city, the higher its ozone level. Is the relationship significant? Assuming the conditions for inference are satisfied, find the t-value and P-value to test the appropriate hypothesis. State your conclusion in context.
b) Do you think that the population of a city is a useful predictor of ozone level? Use the values of both R2 and s in your explanation.