Answer to Question #28664 in Statistics and Probability for Kiara Elmore

Question

2. Explain to a friend who knows no statistics, what 95% confidence means.

Answer 1

In statistics, a confidence interval is a type of interval estimate of a population parameter and is used to indicate the reliability of an estimate. It is an observed interval (i.e. it is calculated from the observations), in principle different from sample to sample, that frequently includes the parameter of interest if the experiment is repeated. Confidence intervals consist of a range of values (interval) that act as good estimates of the unknown population parameter. The level of confidence of the confidence interval would indicate the probability that the confidence range captures this true population parameter given a distribution of samples. It does not describe any single sample. This value is represented by a percentage, so when we say, "we are 95% confident that the true value of the parameter is in our confidence interval", we express that 95% of the observed confidence intervals will hold the true value of the parameter.