twilight (version 1.48.0)
Estimation of local false discovery rate
Description
In a typical microarray setting with gene expression data
observed under two conditions, the local false discovery rate
describes the probability that a gene is not differentially
expressed between the two conditions given its corrresponding
observed score or p-value level. The resulting curve of
p-values versus local false discovery rate offers an insight
into the twilight zone between clear differential and clear
non-differential gene expression. Package 'twilight' contains
two main functions: Function twilight.pval performs a
two-condition test on differences in means for a given input
matrix or expression set and computes permutation based
p-values. Function twilight performs a stochastic downhill
search to estimate local false discovery rates and effect size
distributions. The package further provides means to filter for
permutations that describe the null distribution correctly.
Using filtered permutations, the influence of hidden
confounders could be diminished.