Normalization methods applied to the MAQC data with unequal treatment groups. Labels on the x-axis indicate method names and the treatment group sizes. Numbers indicate the sizes of treatment groups A and B, respectively, on the AFX platform and B and A, respectively, on the ILM platform, in terms of number of assays. For example, the label "method.m.n" indicates that the method "method" was applied to a data set containing m group A AFX assays, n group B AFX assays, m group B ILM assays, and n group A ILM assays. Boxes show the interquartile range and whiskers extend to an additional 1.5 times the interquartile range. Values outside the whiskers are plotted as circles. Notches are drawn such that non-overlapping notches are strong evidence of differing medians [61, 45].