Figure 6From: A probe-treatment-reference (PTR) model for the analysis of oligonucleotide expression microarraysThe frequency of being the "implicit optimal reference". It illustrates the frequency of reference arrays which have been served as the "implicit optimal reference" across all the probe-sets. It is computed from the residual assessment after the PTR method with the invariant-set normalization on the data set "Expt-3-4".Back to article page