for the decision rule to reject the null hypothesis when the P-value is smaller than a fixed threshold. The fixed threshold is called the significance level. This decision rule is not error free and rejecting the null hypotheses when it is true is known as type I error. Type II error is defined as accepting the null hypothesis when the alternative hypothesis is true and it is related to the power of the test [65]. This approach requires a method to estimate the association and a significance level used as the threshold for the P-value. We will discuss the former here, and address the latter issue in the section about multiple comparisons.
