Created by Kristoffer Magnusson, from an idea by Daniel Lakens and formulas from JP de Ruiter.

Many know that *p*-values follow an uniform distribution when the null hypothesis is true. But what about when the null isn't true? This visualization shows the distribution of *p*-values when comparing the means of two independent samples. Check out this blog post by Daniel Lakens for more information.

Log x-axis

This visualization is based on a **two-sample Z-test**, i.e. we assume that the true standard deviation is known. In real life this is often not the case, which is why t-tests are much more common. When the effect is nonzero p-values from t-tests follow a non-central

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