Confidence Interval Calculator
Enter a sample and a confidence level to get the interval, the margin of error and the working. Then run repeated samples to see what a 95% confidence level really means.
What you can do
- Intervals for means with t or z, from summary values or raw data
- Intervals for proportions, with the Wilson interval beside the textbook one
- A simulation of repeated samples, counting how many intervals capture the truth
- The critical value shown on its distribution