Hypothesis Testing Simulator

An interactive demonstration of hypothesis testing — showing how alpha, effect size, sample size, and power interrelate.


What it does

  • Displays null and alternative distributions
  • Shows significance level (alpha) and rejection region
  • Illustrates Type I error, Type II error, and statistical power
  • Adjust parameters to see how power changes

Key concepts illustrated

  • Type I error (alpha) — rejecting H0 when it's true (false positive)
  • Type II error (beta) — failing to reject H0 when H1 is true (false negative)
  • Power (1 - beta) — probability of correctly detecting a real effect
  • Larger effect sizes increase power
  • Larger samples increase power
  • Stricter alpha decreases power

This makes power analysis intuitive rather than abstract — excellent for teaching and for understanding the design decisions behind your study.

A UniversalChatBot is available for discussion.