Interval Estimate Calculator For Population Proportions

Introduction & Importance

Interval estimate for population proportions is a statistical method used to estimate the range within which a population proportion lies with a certain degree of confidence.

How to Use This Calculator

1. Enter your sample size.
2. Enter the proportion observed in the sample.
3. Select your desired confidence level.
4. Click ‘Calculate’.

Formula & Methodology

The formula used is: p ± z * sqrt[(p * (1 - p)) / n], where p is the proportion, z is the z-score based on the confidence level, and n is the sample size.

Real-World Examples

Data & Statistics

Comparison of Confidence Intervals

Sample Size	Proportion	90% CI	95% CI	99% CI

Expert Tips

• Larger sample sizes result in narrower intervals.
• Confidence intervals give an idea of the range within which the true population proportion lies.

Interactive FAQ

What is a confidence interval?

A confidence interval is a range of values around an estimate, within which we are confident that the true value lies.

For more information, see CDC’s guide on confidence intervals.