What is a confidence interval?

A confidence interval is a statistical concept that provides a range of values, derived from a data set, that is likely to contain the true value of an unknown parameter or variable. This interval is constructed around a sample statistic, such as the mean, and is calculated based on the sample data and a specified confidence level, often expressed as a percentage (e.g., 95% confidence interval). The range indicates the degree of uncertainty associated with the estimate, allowing researchers and analysts to assess how much trust they can place in the sample statistic.

The correct understanding of a confidence interval is crucial in data science and statistics, as it encapsulates both the variability inherent in sampling data and the precision of the estimator being used to infer population parameters. By communicating the range within which the true value is expected to lie, it provides insight into the reliability of the data analysis and supports decision-making processes based on statistical evidence.