Hypergeometric over-representation analysis.

For each pathway in the KEGG graph, computes a p-value using the hypergeometric test: M = total number of compounds in the background n = number of compounds in the pathway N = number of input compounds k = number of input compounds in the pathway p-value = P(X >= k) where X ~ Hypergeometric(M, n, N)

Lower p-values indicate pathways with more overlap than expected.