Confidence interval

An interval estimate of a population parameter. A confidence interval is therefore an interval of values, calculated from a random sample taken from the population, of which any number in the interval is a possible value for a population parameter.

The word ‘confidence’ is used in the term because the method that produces the confidence interval has a specified success rate (confidence level) for the percentage of times such intervals contain the true value of the population parameter in the long run. 95% is commonly used as the confidence level.

Curriculum achievement objectives reference
Statistical investigation: Level 8