Confidence Interval Calculator
Compute confidence intervals using the z distribution (normal approximation).
About This Calculator
The Confidence Interval Calculator computes the range likely to contain a population parameter. It calculates intervals for means using z-scores for various confidence levels (90%, 95%, 99%).
How to Use
- Enter the sample mean and standard deviation
- Enter the sample size
- Select the confidence level
- Click Calculate to see the interval
Practical Use Cases
- Research: Report statistical findings with uncertainty
- Polls: Calculate margin of error
- Quality Control: Set specification limits
- Medical Studies: Report treatment effect ranges
- Business: Estimate parameter ranges
? Frequently Asked Questions
How accurate is this
This calculator uses standard formulas and provides accurate results for typical use cases. For professional or critical applications, always verify results with certified professionals or official sources.
Is this calculator free to use?
Yes, this Statistics Confidence Interval Calculator is completely free to use with no registration required. You can use it as many times as needed without any limitations.
Can I use this on mobile devices?
Absolutely! This calculator is fully responsive and works perfectly on smartphones, tablets, and desktop computers.
How do I interpret the results?
The results are displayed clearly with appropriate units. Refer to the "About This Calculator" section for detailed information.