Question13. Each person in a simple random sample of 2,000 received a survey, and 317 people returned their survey. How could nonresponse cause the results of the survey to be biased? (A) Those who did not respond reduced the sample size, and small samples have more bias than large samples. (B) Those who did not respond caused a violation of the assumption of independence. (C) Those who did not respond were indistinguishable from those who did not receive the survey. (D) Those who did not respond represent a stratum, changing the simple random sample into a stratified random sample. (E) Those who did respond may differ in some important way from those who did not respond.