Chapter 6 of 10All chapters
Chapter 6 of 10
Confidence and error
Saying how sure you are.
Margin of error
A survey result is an estimate with a range around it. A confidence interval says that a method like this one captures the true value in, say, 95 percent of repeated samples.
- It describes the procedure over many samples, not this single result.
- Two intervals that overlap heavily are not meaningfully different.
Reporting honestly
A figure quoted without an interval is quoted without its uncertainty. Small subgroups have wide intervals, which is why breakdowns often mean nothing.