A P-value based on a single test is misleading if you perform several tests. The Bonferroni procedure gives a significance level for several tests together. Level a then means that if all the null hypotheses are true, the probability is a that any of the tests rejects its null hypothesis. If you perform two tests and want to use the a = 5% significance level, Bonferroni says to require a P-value of 0.05/2 = 0.025 to declare either one of the tests significant. In general, if you perform k tests and want protection at level a, use alk as your cutoff for statistical significance for each test. A researcher has performed 12 tests of significance and wants to apply the Bonferroni procedure with a = 0.05. The calculated P-values are 0.039, 0.549, 0.003, 0.316, 0.001, 0.006, 0.251, 0.031, 0.778, 0.012, 0.002, and