Position conservation information helps classification. In both figures, the y-axis is the negative log p- value of the log likelihood ratio of a motif in a dataset. The x-axis in (a) is the dataset index, in (b) it is the p-value of the Kolmogorov-Smirnov test on positions of a motif's binding sites, assuming a uniform distribution. Each point represents one dataset. For the same reason as in Figure 1, no "Real" type datasets are included. In (b) the straight green line decently classifies the two sets of points.