Nonresponse bias occurs when which of the following happens in a probability sample?

• A. All individuals in the sample respond, but the sample size is too small.
• B. The data are collected using a census rather than a sample.
• C. The sampling method is random and every individual has an equal chance of being selected.
• D. Some individuals selected for the sample do not respond, and their nonresponses are related to the variable of interest.

Answer: (D)

Verified step by step guidance

1. Understand the concept of nonresponse bias: it occurs when some individuals selected for a sample do not provide responses, and this nonresponse is related to the variable being studied.
2. Recognize that nonresponse bias affects the representativeness of the sample because the missing data are not random but systematically related to the outcome of interest.
3. Evaluate each option by checking if it describes a situation where nonresponse is related to the variable of interest:
4. - Option 1 describes all individuals responding but a small sample size, which is not nonresponse bias but a sample size issue.
5. - Option 2 describes using a census, which means no sampling and thus no sampling bias or nonresponse bias.
6. - Option 3 describes a proper random sampling method, which is ideal and does not imply nonresponse bias.
7. - The correct scenario is when some individuals do not respond and their nonresponse is related to the variable of interest, causing nonresponse bias.