Statistics & Probability Calculators

A p-value of 0.03 is a 3% chance of seeing this result if nothing is going on. It is not a 97% chance you are right, and the difference is most of what goes wrong with a reported result. These calculators work through the tests and intervals that answer the question properly — t-tests, chi-square, confidence intervals, sample size, correlation — and show every intermediate value against a published worked example, so the number can be checked rather than trusted.