Figure 4

P-values for testing the hypothesis of no differential expression as a function of the median ANOVA (1-p) scores for the case of 11 probes per probe set. These charts show the unadjusted p-values corresponding to median ANOVA (1-p) scores for a specific number of probes per probe set. Similar curves can be obtained for any number of probes per probe set by means of the pbeta function in the R package stats, or the tools for working with sums of random variables in the R package distr. Figure 4(a) shows the full curve, while Figure 4(b) zooms in on the portion of the curve most involved with deciding on the question of differential expression.