Doug notices in his sample studies that marijuana users are much more likely to report using heroin than people who do not use marijuana.He concludes that marijuana must be a gateway drug-a drug that leads to the use of harder substances.What's wrong with Doug's conclusion?
A) His sample data does not demonstrate causality.
B) Marijuana users cannot be trusted to report their behavior honestly and accurately.
C) Doug could never really know without trying marijuana himself and seeing whether it leads to heroin use.
D) Marijuana users would likely be afraid of needles because they are used to smoking their drug of choice.

Question

Quizplus · Accepted Answer

Doug's conclusion is flawed because correlation does not imply causation. His sample data shows a correlation between marijuana use and heroin use, but it does not prove that marijuana use causes heroin use. Other factors could be influencing both behaviors.

Doug Notices in His Sample Studies That Marijuana Users Are