Each person in a simple random sample of 1,500 received a survey, and 412 people returned their survey. How could nonresponse cause the results of the survey to be biased?

Non Response: In conducting a survey some people did not respond to our survey, this sometimes affects our survey result very much.

For Example: It can happen that some people may refuse to participate in a survey, as the question asked to people contain personal detail or illegal activities or asking any embarrassing information, so people refused to participate in the survey. This non-response cause the results of the survey to be biased