Distribution pattern of fold change values in a microarray data and determination of minimal gene set size in PAGE. A and B. A Histogram (A) and a quantile-quantile (Q-Q) plot against standard normal distribution (B) of fold change values from microarray data set. The diabetic muscle microarray data set  was analyzed as described in Methods section. The fold change values between normal and patient groups were calculated and used to draw histogram (A) and Q-Q plot (B). C and D. A Histrogram (C) and a Q-Q plot (D) of an average of 10 randomly sampled values from fold change values of diabetic muscle microarray data. Kolmogorov-Smirnov normality test was performed with a null hypothesis that distribution is normal. For the distribution of fold change values (A and B), the null hypothesis was rejected (D = 0.08, p-value < 2.2e-16). For the distribution of an average of 10 randomly sampled values from fold change values (C and D), the null hypothesis was not rejected (D = 0.0239, p-value = 0.1783).