Explain what a population is.

• A. A group whose members may or may not interact with one another, but share at least one characteristic (ex. age, gender, ethnicity, residence, common health issue)
• B. A single individual's health status
• C. All residents of a country
• D. Patients seen in a hospital in a day

Answer: (A)

In health science, a population is defined by a group of people who share at least one characteristic or a common setting, and they may interact or not. This shared attribute—such as age, gender, ethnicity, where they live, or a common health issue—binds the group for analysis and public health planning.

That’s why the best choice is the one describing a group linked by a common characteristic. It captures the idea that a population isn’t defined by a single person, nor simply by being in the same country or by the clinical setting of a hospital on a particular day. The other descriptions describe individuals, or broad geographic scopes or convenience samples, which don’t specify the defining shared characteristic that makes a population relevant for study and comparison.