Question

A professor believes that students who smoke cigarettes tend to have lower grades. He collects data from 1326 randomly selected students at his university and discovers that, on average, students who smoke cigarettes do indeed tend to have lower grade point averages than students who do not smoke. Does this study give strong evidence that smoking cigarettes causes lower grades?

Answer 1

No.

Explanation:

His finding that "students who smoke cigarettes do indeed tend to have lower grade point averages than students who do not smoke" implies that there can be a connection between smoking and grades. It does not specifically refer to a causal relation that smoking causes lower grades. People who make bad decisions may choose not to study well and may choose to smoke.