Type I and type II errors (source code)

= Type I and type II errors
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= Type I error
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= Type II error
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For a <null hypothesis> $H_0$, a <type I error> rejects $H_0$ when it is true, while a <type II error> does not reject $H_0$ when the alternative is true. If a test does not reject $H_0$ on an event $A$, their <conditional probabilities> are $\alpha=P_0(A^c)$ and $\beta=P_1(A)$. Nonrejection does not establish the truth of the <null hypothesis>.