Figure 3

Error vs. mean shows independence following log ₁₀ transformation. Data generated from real-time RT-PCR assay for IL18 on RNA extracts from human gastric mucosa. Upper left plot shows error (numerical difference between duplicate values) vs. mean (of duplicate values) for values derived by the NLR method. As the error tends to increase with the mean, a plot based on log₁₀ transformed copy numbers is shown (upper right), and independence can be observed. The same pattern was observed for the bias (difference between NLR- and CT-generated values), in the lower left plot. Again, a log₁₀ transformation of the copy number values (lower right) can remove the trend, and independence can be observed.