In a Laboratory, Smokers Are Asked to Drive Using a Computerized

Multiple Choice

In a laboratory, smokers are asked to drive using a computerized driving simulator and cover the maximum distance possible, while avoiding rear-end collisions. Some volunteers are given a real cigarette to smoke immediately before the test. Others smoke a fake cigarette without nicotine. The number of collisions the two groups make is to be compared. In this study, the independent variable is:

A) the use of nicotine.
B) the use of a driving simulator.
C) the number of collisions.
D) the speed of each driver.