A confidence interval is a range of values, derived from sample data, that is likely to contain the true population parameter (such as a mean or proportion) with a specified level of confidence (e.g., 95%). It provides an estimate of the uncertainty or precision of the sample statistic, offering a range within which the true value is expected to lie.

For example, a 95% confidence interval for a mean of 50 might be (48, 52), meaning we are 95% confident the true population mean is between 48 and 52.