What Is a Confidence Interval?
A confidence interval (CI) is a range of values, derived from sample data, that is likely to contain the true population parameter. It is expressed with a confidence level—commonly 90%, 95% or 99%—that indicates how confident we are that the interval captures the unknown value.
When Do You Need a Confidence Interval?
Use a CI whenever you want to:
- Summarize the precision of an estimate (e.g., a mean or proportion).
- Compare two groups while accounting for sampling variability.
- Make data‑driven decisions in business, healthcare, or research.
Step‑by‑Step: Calculating a Confidence Interval for a Mean
Below is a practical method for a 95% CI of a population mean when the sample size is small (n
About Antonov Ivanov
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Antonov Ivanov has been contributing to eKnaw for over a year, focusing on practical solutions and life improvements through simple, actionable advice.
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