Confidence Interval Calculator
Estimate the confidence interval for a population mean based on sample data.
Confidence Interval: —
Uses the normal (Z) approximation for confidence intervals.
Example
Sample mean = 50
Standard deviation = 10
Sample size = 100
Confidence level = 95%
→ Confidence Interval ≈ [48.04 , 51.96]
Standard deviation = 10
Sample size = 100
Confidence level = 95%
→ Confidence Interval ≈ [48.04 , 51.96]
What is a confidence interval?
A confidence interval provides a range of values within which the true population parameter is likely to fall, based on sample data.
Why use a confidence interval?
Confidence intervals are widely used in statistics, research, data analysis, and quality control to quantify uncertainty in estimates.
Frequently Asked Questions
Is this a Z or T confidence interval?
This calculator uses the Z distribution. For small samples or unknown variance, a T-test may be more appropriate.
What confidence level should I choose?
95% is the most common choice, but higher levels give wider intervals.