A researcher uses an anonymous survey to investigate the television-viewing habits of American adolescents. Based on the set of 356 surveys that were completed and returned, the researcher finds that these students spend an average of 3.1 hours each day watching television. For this study, the set of 356 students who returned surveys is an example of a _______.

• A. Population
• B. Sample
• C. Census
• D. Parameter

Answer: (B)

This question tests how we distinguish between population and sample. The 356 adolescents who completed and returned the survey are only a part of all American adolescents who could have been surveyed. That subset is called a sample. If we had gathered information from every American adolescent, that would be a census. A parameter is a numerical value that describes the entire population (the true average across all adolescents). Since the data come from the subset, the resulting average of 3.1 hours is a statistic derived from the sample, not a population parameter.