Comparison of the results of microarray and Northern blot analyses. Data were obtained from a time-course experiment for cold treatment of rice seedlings . a. In the microarray analysis, intensity data were normalized by means of the three-parameter lognormal distribution model, and transformed to ratio-basis in comparison with control plants. The number of data points was 33, and the correlation coefficient was r= 0.8579. b. The same data set as in a., but the background of microarray data was subtracted using local background method  and then the data were normalized by globalization. The correlation coefficient was 0.7613. c. The same as b., but normalized using LOWESS method . The correlation coefficient was 0.7845.