Array-wise accuracy values with different signal ratios. The blue bars correspond to Test over Control ratio (T/C), green bars to the logarithm of the Test over Control ratio (Log(T/C) and the brown bars to the Control over Test ratio (C/T). Each cluster of three bars was obtained from the same array. The top row shows results for Streptococcus pneumoniae arrays with the mix control, the center row for S. pneumoniae arrays with the TIGR4 control and the bottom row for Staphylococcus aureus arrays using a single strain control. In all arrays a Normal-Uniform mixture model was adjusted to non-normalized signal ratios.