This package is intended to provide a method whereby the P-values of a set
of GO annotations can be determined for a set of genes, based on the number
of genes that exist in the particular genome (or in a selected background
distribution from the genome), and their annotation, and the frequency with
which the GO nodes are annotated across the provided set of genes. The
P-value is simply calculated using the hypergeometric distribution as the
probability of x or more out of n genes having a given annotation, given
that G of N have that annotation in the genome in general. We chose the
hypergeometric distribution (sampling without replacement) since it is more
accurate, though slower to calculate, than the binomial distribution
(sampling with replacement).