The MONOX data set contains the results of a study of carbon monoxide levels and traffic intensity at a busy intersection. For twelve hours, the approximate number of cars passing through the intersection each hour is recorded (multiply values of variable CARS by 1000 for the approximate numbers). The carbon monoxide concentration (in parts per million) at the intersection is recorded hourly.
This data set is appropriate for simple linear regression modeling carbon monoxide levels (variable CO) as a function of traffic intensity (variable CARS).