Figure 4
Spiked-in data. (A) Average observed ln intensity plotted against normalized ln concentration for 42 spiked-in genes of the Affymetrix spike-in experiment. The observed concentrations are adjusted so that all lines have the same intercept at a ln concentration of 2.8 (16 pmol). The solid line without symbols represents the ideal slope-1 line. (B) The accuracy of picking up the spiked-in genes. The significance between two successive spike-in concentrations (0–0.125; 0.125–0.25; etc.) was calculated for each gene. The number of genes where calculated per spike-in concentration that significantly where up regulated, and presented on the y-axis as percentage. This means that at "1" all 42 genes where significant at a given concentration.