Question

15.32 Freeway exhaust and atherosclerosis. A February 2010 news story on cnet.com reported that the artery walls of people living close to a freeway thicken faster than the walls of those who don’t. Researchers correlated changes in artery wall thickness of subjects with estimates of outdoor particulate levels at each subject’s home. Does this mean that you can reduce atherosclerosis (the thickening and calcification of arteries) by avoiding living near a freeway? Why?

Answer 1

No

Reason: The 2 variables: x = Living close to a freeway and y = Thickening the artery walls of people

are positively correlated does not imply that x = Living close to a freeway causes y = Thickening the artery walls of people.

This correlation is due to the Confounding Variable z = traffic pollution of the vehicles passing through the freeway.

The fact is that living close to a freeway causes the people inhale the polluted exhaust of the the vehicles passing through the freeway.which makes the thickening of the artery walls of the people living there leading to heart disease and strokes at a faster rate than the general public.