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A "confidence interval" is a measure in statistics that indicates the range of values within which a population parameter is estimated to be included. The confidence interval is used when making estimates about the population based on sample data, and it quantitatively expresses the uncertainty of the estimate.
1. Expression of Estimation UncertaintyA confidence interval expresses the uncertainty of how accurately the estimated value obtained from a sample reflects the population parameter. This allows for the evaluation of the reliability of the estimate.2. Aid in Interpretation of ResultsIn interpreting the results of research or data analysis, confidence intervals are very useful. For example, a narrow confidence interval indicates a stable estimate, while a wide one indicates a large variation in the data.3. Support for Hypothesis TestingConfidence intervals are also used in hypothesis testing. For example, if the confidence interval does not include zero when investigating the effect of a treatment, it can support the conclusion that the treatment is effective.4. Assistance in Decision MakingIn the decision-making process of business and science, confidence intervals play an important role. By considering the confidence interval, risks can be managed and more informed decisions can be made.5. Evaluation of Research ReproducibilityConfidence intervals are also used when evaluating the reproducibility of research. If the confidence intervals obtained in different studies overlap, it indicates that the results are consistent and are considered to have high reproducibility.6. Communication of UncertaintyConfidence intervals are an effective tool for communicating data uncertainty to others. This can make the interpretation of data more transparent and easier to understand.