Question

Suppose that data collected from police reports of motor vehicle crashes show a moderate positive correlation between the speed of the motor vehicle at the time of the crash and the severity of injuries to the driver. Answer the following question based only on this information.

True or false: Traveling faster in a motor vehicle at the time of a crash causes more severe injuries to the driver.
A. True
B. False

Answer 1

B. False

Explanation:

A moderate positive correlation, e.g. r = 0.5 or 0.6, shows that there is some relationship between driving faster and accidents that result in more severe injuries. But that relationship is not very strong or solid and can result from other variables being involved or simply randomness. You cannot affirm that X causes Y if the correlation is not strong.