Figure 2.

Empirical measurement of the ChipStat null distribution. Mammary gland tissue was harvested from six separate, biologically identical pools of FVB (MTB) mice, and hybridization data to Affymetrix MG_U74Av2 microarrays was obtained. Comparisons of all possible three versus three combinations (total 20) were performed using ChipStat (p_ps = 0.05), and the number of significant increases was tabulated for all probe sets containing 16 probe pairs per probe set (total = 11,820). The cumulative average probability is shown as a function of the number of probe pairs that increase within the probe set.