How to use this calculator
Choose a parameter and enter summary statistics or counts.
Formula and method
Mean: estimate ± critical × standard error. Proportion: Wilson score. Difference of proportions: Newcombe combination of Wilson limits.
Worked example
Mean 50, SD 10, n=100: 95% t interval approximately [48.016, 51.984].
Assumptions and supported scope
Two-sided intervals only. No paired, clustered, weighted or finite-population correction. Group differences are group 1 minus group 2.
Method references
Method and worked example checked against the calculator implementation. About our methods · Report a correction