Confidence Interval
Calculator
Quantify the uncertainty in your sample data. Determine the range where your true population mean likely lies with professional precision.
Calculation Result
48.0400 to 51.9600
Margin of Error
± 1.9600
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Create SurveyWhat is a Confidence Interval?
A confidence interval is a range of values that likely contains the true population parameter you're trying to estimate. When you collect sample data, you can't know the exact population mean, but an interval gives you a range where the true mean probably falls.
The Formula
CI = x̄ ± z × (σ / √n)How to interpret the results
A 95% confidence level doesn't mean there is a 95% probability that the population mean is in the interval. It means that if you repeated your sampling process 100 times, about 95 of those generated intervals would contain the true population mean.
Sample Size (n): Larger samples lead to narrower, more precise intervals.
Confidence Level: Higher confidence (99%) requires a wider interval to be "sure."