Functional enrichment in differentially expressed genes. These graphs produced by QiSampler show the average performance of the z-score comparing gene expression values between 30 OTA and 24 WT samples to select gene probes related to oxidoreductase activity in a thyroid microarray gene expression dataset . The performance was averaged over 1000 repetitions with a sampling rate of 25% representing 34/137 known items and 34/3684 novel items. Dashed lines represent randomized data. The precision increases with the z-score cutoff indicating functional enrichment in the upregulated genes.