Your result of 385 is calculated using the Cochran Formula. Based on a 95% confidence level, your data will reflect the true population within a 5% margin of error.
Guide
1. Population Size: Enter the total number of people in your target group. Use a large number if the population is unknown.
2. Confidence Level: How certain you need to be. 95% is the industry standard.
3. Margin of Error: The amount of "wiggle room" you allow for results.
Facts
Did you know? Even for a population of 7 billion people, with a 5% margin of error and 95% confidence, you only need a sample of 385 people. Statistical power scales logarithmically!
Additional Tips
Always aim for a slightly higher sample size than calculated to account for non-responders or "dirty data" in your survey process.
Use Cases
- A/B Testing for Websites
- Political Polling
- Medical Clinical Trials
- Market Research Surveys
About This Tool
This tool uses the standard normal distribution Z-scores and Cochran’s Correction for finite populations to provide a production-grade statistical requirement.
Examples
Small Business: Customer base of 500, 95% Conf, 5% Error = 218 samples.
City Survey: Population 100k, 99% Conf, 1% Error = 14,310 samples.
| Feature | Details |
|---|---|
| Price | Free |
| Rendering | Client-Side Rendering |
| Language | JavaScript |
| Paywall | No |
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