Comparison between the observed (red) and simulated (blue) plots of F -values versus -values. F-values were observed from real (red) and simulated (blue) microarray data sets of 3770 genes and 6 replicates. -value yielded by randomly splitting approach is an estimate in null f-distribution. F-distribution from simulated data set without treatment effects is null distribution. Ranked F-values corresponds to ranked -values.