Worse-case confidence interval width
Public opinion polls often ask questions about a range of topics. Several proportions are usually estimated from the answers to different questions in the poll. A 95% confidence interval could be separately given for each proportion, but a worst-case '± value' can be given that applies to all separate estimates. This is called the margin of error of the poll.
Illustration
Example
A numerical example illustrates the use of margin of error in a survey.