Lower and Upper Bound Confidence Interval Calculator (No Standard Deviation)
Lower and upper bound confidence intervals are essential in statistics, providing a range within which the true population parameter is likely to fall. This calculator helps you determine these bounds without needing the standard deviation.
- Enter the sample size.
- Select the desired confidence level.
- Click ‘Calculate’.
The formula used is: Z * sqrt[(p * (1 - p)) / n], where Z is the Z-score corresponding to the confidence level, p is the proportion (assumed to be 0.5 for this calculator), and n is the sample size.
| Sample Size | 90% Interval | 95% Interval | 99% Interval |
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- Always use the appropriate confidence level for your analysis.
- Consider the sample size; larger samples provide narrower intervals.
What is a confidence interval?
A confidence interval is a range of values around a sample statistic (like the mean) that indicates the reliability of the statistic.
For more information, see CDC’s guide on confidence intervals and this educational resource.