Figure 1. Plot of the p-values computed according to different statistical tests. In abscissa is represented the number of clusters sorted from the most reliable to the least reliable (with respect to the stability indices computed by random projections and using the k-means clustering algorithm). The the p-values are represented in log scale. The straight horizontal dashed line, represents the 0.001 significance level: K-clusterings above the dashed line are significant, that is their reliability significantly differ from the k-clusterings below the dashed horizontal line.