Accuracy for the methods of analysis applied. Each dot represents one Streptococcus pneumoniae array. The left plot represents the 8 arrays using the TIGR4 control, and the rights plot the 8 arrays using the mix control. The bottom boxes along the x-axis identify the different combinations of methods tested: the mixture model is either based on the Gamma distribution (Gamma) or in the Normal and Uniform distributions (Norm./Unif.); ratios can be normalized with the loess procedure (Normalization); and the signal ratio can be Test over Control signal (T/C), logarithm of the Test over Control (Log(T/C) or Control over Test (C/T). The order of the different method combinations is defined by the resulting mean accuracy. Each method combination was applied to all the 16 arrays.