Confidence Interval of a Proportion Calculator
Introduction & Importance
Calculating the confidence interval of a proportion is crucial in statistics to estimate the population proportion within a certain degree of confidence.
How to Use This Calculator
- Enter the sample size.
- Enter the proportion.
- Select the confidence level.
- Click “Calculate”.
Formula & Methodology
The formula for calculating the confidence interval of a proportion is:
p ± z * sqrt[(p * (1 – p)) / n]
Where:
- p is the proportion
- z is the z-score based on the confidence level
- n is the sample size
Real-World Examples
Data & Statistics
| Sample Size | Proportion | 90% CI | 95% CI | 99% CI |
|---|
Expert Tips
- Use larger sample sizes for more precise estimates.
- Consider the margin of error for your needs.
- Always round the confidence interval to a reasonable number of decimal places.
Interactive FAQ
What is a confidence interval?
A confidence interval is a range of values around an estimate that indicates the reliability of the estimate.