Creep

Mathematics

4 November, 23:11

Each person in a simple random sample of 1,800 received a survey, and 267 people returned their survey. How could nonresponse cause the results of the survey to be biased?

-Those who did not respond reduced the sample size, and small samples have more bias than large samples.

- Those who did not respond caused a violation of the assumption of independence.

-Those who did not respond are indistinguishable from those who did not receive the survey.

-Those who did not respond may differ in some important way from those who did respond.

-Those who did not respond represent a stratum, changing the random sample into a stratified random sample.