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. 2021 Jun 9;16(6):e0245824. doi: 10.1371/journal.pone.0245824

Table 1. Formulas and explanations of statistical concepts.

Statistical concept Formula Explanation
Family-wise error rate αFW = 1- (1- αPC)C where C refers to the number of comparisons performed, and αPC refers to the per contrast error rate, usually 0.05
Bonferroni correction p’i = npi ≤ α the p-value of each test (pi) is multiplied with the number of performed statistical tests (n). If the corrected p-value (p’i) is lower than the significance level, α (usually 0.05), the null hypothesis will be rejected and the result will be significant
Sidak-correction p’i = 1- (1—pi)n ≤ α. where pi refers to the p-value of each test, and n refers to the number of performed statistical tests (n)
False discovery rate FDR = E [V / R] where E refers to the expected proportion of null hypotheses that are falsely rejected (V), among all tests rejected (R), thus it calculates the probability of an incorrect discovery.
Storey’s positive FDR FDR (t) = (π0 x m x t) / S(t) where t represents a treshold between 0 and 1 under which p-values are considered significant, m is the number of p-values above the treshold (p1, p2, pm), π0 is the estimated proportion of true nulls (π0 = m0 / m) and S(t) is the number of all rejected hypotheses at t
Benjamini and Yekutieli FDRi ≤ (n x pi)/(nRi x c(n))’ where c(n) is a function of the number of tests depending on the correlation between the tests. If the tests are positively correlated, c(n) = 1
Proportion of false positives (PFP) PFP = E (V) / E (R) where E refers to the expected proportion of null hypotheses that are falsely rejected (V), among all tests rejected (R). V and R are both individually estimated
q-value q(pi) = min FDR (t) the q-value is defined as the minimum FDR that can be achieved when calling that "feature" significant