Table 2.

List of methods used for combining p-values to assess final enrichment significance.

Methods	Transformed variable	Test statistic	Dist. under H0	Reference
Inverse Normal	Zk = Φ−1(pk)	$T={\sum }_{k=1}^K{w}_k{Z}_k$	N (0, 1)	39
Meanp	$\overline{p}={\sum }_{k=1}^K{p}_k/K$	$W=(0.5-\overline{p})\sqrt{12K}$	N (0, 1)	40
Inverse Chi-Square	Zk = −2logpk	$L={\sum }_{k=1}^K{Z}_k$	χ²2Kdf	41,42
Logit	Sk = log[pk/(1−pk)]	$S={\sum }_{k=1}^K{S}_k$	t5K+4 df	43

p_k: statistical significance value of k-th gene sample; Φ, Φ⁻¹: standard normal cumulative distribution function and its inverse respectively; K: Number of random gene samples; df: degrees of freedom; H₀: Competitive null hypothesis; N(): Normal distribution; t: Central t-distribution; χ²: Central Chi-square-distribution.