aPearson correlation coefficient assumes data are normally distributed. bSpearman correlation coefficient assumes data are symmetrical. cThe weighted Kappa statistic assumes data are ordinal. . Pearson and Spearman correlation coefficients were calculated from median normalized and log transformed data. All genes were categorized according to their normalized expression level (undetectable, 0; low, 0 to 1.3; medium 1.3 to 3.0; or high, >3.0) for calculation of the weighted Kappa statistic. Results are the average of the three pairwise comparisons among three hybridizations of each type of RNA.