(a) Variance plots for real and randomized data. The percent variance explained by each cluster, both for the original data, and for an average over three randomized versions. (b) Gap estimates of cluster size. The gap curve, which highlights the difference between the pair of curves, is shown.
Hastie et al. Genome Biology 2000 1:research0003.1 doi:10.1186/gb-2000-1-2-research0003