4.2.1—Hypothesis tests

Set a null hypothesis H₀ and an alternative H₁ before calculating. The test statistic or p-value measures how surprising the sample would be if H₀ were true.

Choose a significance level α, identify the rejection region or compare p with α, and state the decision in context. A one- or two-tailed alternative changes the region.

At α=0.05, p=0.03 leads to rejection of H₀; it does not prove H₁, only that the observed result is sufficiently inconsistent with the null model.

Failing to reject H₀ is not accepting it, and statistical significance does not measure the size or practical importance of an effect.