Figure 5

MA-plots of QC LMS controls for two arrays. MA-plots for arrays 91 (a) and 19 (b) which were assigned the highest and lowest quality weights respectively. Here M = log₂(R/G) is the spot log-ratio and A = (log₂G + log₂R)/2 is the spot log-intensity. Dashed lines show the theoretical M values from Table 1. The controls from array 91 consistently recover the true spike-in log-ratios and are assigned high weight (v₉₁ = 3.68), whereas the log-ratios from array 19 are considerably more variable, resulting in a very low weight (v₉₁ = 0.11).