The accompanying data was read from a scatter plot in the article “Urban Emissions Measured with Aircraft” (J. of the Air and Waste Mgmt. Assoc., 1998: 16–25). The response variable is , and the explanatory variable is . CO

NOy a 5 .01 CO 50 60 95 108 135 2.3 4.5 4.0 3.7 8.2 CO 210 214 315 720

NO 5.4 7.2 13.8 32.1 y

NOy

a. Fit an appropriate model to the data and judge the utility of the model.

b. Predict the value of NOy that would result from making one more observation when CO is 400, and do so in a way that conveys information about precision and reliability. Does it appear that NOy can be accurately predicted? Explain

c. The largest value of is much greater than the other values. Does this observation appear to have had a substantial impact on the fitted equation?