Question

Customers at a fast-food restaurant were invited to complete a brief survey to rate their experiences at the restaurant. One day, 48 customers chose to complete the survey. Which statement best explains why this was probably not a representative sample?

A.
The sample size was too small.

B.
The sample size was too large.

C.
The sample included only those people who chose to complete the survey.

D.
The sample included only those people who were customers at the restaurant.

Answer 1

C. The sample included only those people who chose to complete the survey.

This is a self‑selected (voluntary response) sample, which often is biased because people who opt in differ systematically from those who don't (e.g., very satisfied or very dissatisfied customers).