Psychology I / Observation and Surveys
Practice question · Multiple choice

A survey achieves a 12% response rate from a perfectly drawn random sample. Why does the careful sampling not save it?

Hints
  1. The randomness was in who was invited. Ask who actually decided the final sample.
  2. A survey about civic engagement: who is most likely to fill it in?
Show the answer

B. Because the 12% who replied are self-selected, and the sample was not

Why

Randomisation happened at invitation; selection happened at reply. If the people who bother to answer a survey on civic engagement are the engaged ones, the estimate is biased and no sample size fixes it, the same lesson as the self-selected online study, arriving through the back door.

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