A confidence interval is a statistical tool used to estimate the range within which a population parameter, such as the mean, is likely to fall. It is derived from sample data and provides a measure of uncertainty around the point estimate. Typically expressed with a confidence level, such as 95%, it indicates that if the same sampling process were repeated multiple times, approximately 95% of the calculated intervals would contain the true population mean. Confidence intervals are essential in data analysis and research, as they help convey the reliability of estimates and the degree of variability in the data.