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See it move, then believe it

Statistics Simulations

The six ideas students fight with all semester — as things you can poke. Each one runs in class on the projector and at home on your phone. Every sim ends with a "Try this" challenge; bring your answers to class.

1 · Sampling Distribution Builder

Draw thousands of samples from lumpy, skewed populations and watch the distribution of means turn bell-shaped before your eyes. The Central Limit Theorem, live.

Open the CLT builder →

2 · The p-Value Machine

Run YOUR study, then run ten thousand studies where nothing is going on. Your p-value is literally counted in front of you — and Type I errors happen on schedule.

Open the p-value machine →

3 · Power Explorer

Two overlapping worlds, one critical line. Slide effect size, n, and α to see power move — and discover why n = 20 studies miss half of all real effects.

Open the power explorer →

4 · Correlation Playground

Click to place data points, drag them around, and watch r respond. Build an outlier that fakes a correlation; build a strong pattern r can't even see.

Open the playground →

5 · The Confidence-Interval Dance

A hundred studies, a hundred intervals, one unmoving truth. See exactly what "95% confident" promises — and what it doesn't.

Open the CI dance →

6 · z-Score & Distribution Explorer

The living z table: slide a cutoff along the normal curve and read areas and percentiles. Then watch the t distribution's fat tails deflate as df grows.

Open the explorer →
Sigma says: Formulas describe what these pictures do. If a formula ever stops making sense, come back here, push the buttons, and watch the idea move. Then the formula is just a caption.