What issues are encountered if a researcher sends a survey to 200 randomly selected participants and only 25 respond?

Question

Quizplus · Accepted Answer

The Answer is Answers should include the concept of bias. Those who do respond, and those who do not, may be doing so because of a specific bias toward the research topic, and the responses therefore might include, or omit, crucial data that would be present in a truly random response.

What Issues Are Encountered If a Researcher Sends a Survey