Which of the following is not a voluntary response sample?

• A. A researcher randomly selects 100 students from a university roster to participate in a survey.
• B. An online poll where anyone can choose to participate is conducted.
• C. A newspaper invites readers to submit their views on a recent event.
• D. A radio show asks listeners to call in if they have an opinion on a topic.

Answer: (A)

Verified step by step guidance

1. Understand the definition of a voluntary response sample: it is a sample where participants choose themselves to be part of the survey, often leading to bias because only those with strong opinions tend to respond.
2. Examine each option to identify if participants are self-selecting (volunteering) or if they are selected by the researcher.
3. Option 1: 'A researcher randomly selects 100 students from a university roster' involves random selection, not self-selection, so this is NOT a voluntary response sample.
4. Options 2, 3, and 4 all involve participants choosing to respond (online poll, newspaper readers submitting views, radio listeners calling in), which are examples of voluntary response samples.
5. Conclude that the option involving random selection by the researcher is the one that is NOT a voluntary response sample.