p-values
2 free lessons tagged p-values across Business, Math. Each one is a short sequence of focused steps with narration and a five-question quiz at the end — take them in any order, no signup required.
Peeking: How Watching Your Experiment Ruins It
The most natural behaviour in experimentation, checking results daily and stopping when they look significant, quietly destroys the statistical guarantee everyone thinks they have. This lesson shows the peeking mechanism with honest arithmetic, then the fixes: fixed-horizon discipline, group sequential designs, and always-valid inference.
Estimation and Hypothesis Testing
From raw data to defensible conclusions: derive Maximum Likelihood Estimators for Bernoulli and Gaussian, understand bias-variance in estimation, construct confidence intervals, and learn what p-values actually say — and don't say — including the most common misinterpretation that has corrupted thousands of papers.