What is the purpose of a confidence interval?

The purpose of a confidence interval is to provide a range for estimating a population parameter. It is a statistical tool that allows researchers to make inferences about a population based on sample data. A confidence interval gives a lower and upper bound, within which the true population parameter (such as a population mean or proportion) is expected to fall, with a certain level of confidence (often set at 95% or 99%).

This range is calculated from the sample data and includes a margin of error, which accounts for the variability in the data and the sample size. By using a confidence interval, researchers can quantify the uncertainty associated with their estimates, helping them understand how reliable their findings are in relation to the entire population. This is particularly useful in various fields, including social sciences, healthcare, and market research, where making accurate population estimates is crucial for effective decision-making.