many sample surveys use well - designed rando...
many sample surveys use well - designed random samples, but half or more of the original sample cant be contacted or refuse to take part. any errors due to this nonresponse have no effect on the accuracy of confidence intervals. are included in the announced margin of error. are in addition to the random variation accounted for by the announced margin of error.
Answer
# Brief Explanations:
The margin of error in sample surveys only accounts for random sampling error. Non - response error is an additional source of error not included in the announced margin of error and can affect the accuracy of confidence intervals.
# Answer:
are in addition to the random variation accounted for by the announced margin of error.