Determine If the Following Scenario Is an Observational Study or a Controlled

Multiple Choice

Determine if the following scenario is an observational study or a controlled experiment. A doctor is interested in determining whether a certain medication reduces migraines. She reviews her patients' medical records and finds that a higher proportion of people who take the medication have fewer migraines than those who did not take the medication.

A) Observational study
B) Controlled experiment
C) Neither