Читать книгу Health Psychology - Michael Murray - Страница 111

A confidence interval (CI) is the interval around the mean of a sample that one can state with a known probability contains the mean of the population. A population parameter is always estimated using a sample. The reliability of the estimate varies according to sample size. A confidence interval specifies a range of values where a parameter is estimated to lie. The narrower the interval, then the more reliable the estimate. Typically, the 95% or 99% CI is stated in the results of a study that has obtained a representative sample of values, e.g., the mean heart rate for a sample might be 75.0 with a 95% CI of 72.6 to 77.4. Confidence intervals are normally reported in tables or graphs, along with point estimates of the parameters, to indicate the reliability of the estimates.