Figure 5.

Relationship between SRV and true experiment-to-experiment variability. (a) Nine microarrays were probed with the same cDNA preparation in parallel and data collected from 9 × 6,200 spots. The standard deviation in expression ratios for each spot as measured on nine arrays using a best-fit background and plotted relative to the average SRV for the same spot. The trend-line is indicated. (b) As in a, but with local background subtraction. (c) Generation of unbiased minimum-variance estimates for Z_i by applying SRV and process control flags to inversely weight ratio data as it enters an operational database (see text for details).