Significance p (in %) and variance ratio for the height clusters of the NCEP54 dataset. Significance is assessed against synthetic Markov model datasets constructed using same variance and lag-1 correlation for the indicated number of PCs, as a function of cluster number k. Here p is given as the percentage of synthetic datasets having a variance ratio less than the NCEP54 dataset. (Values greater than 90% are bold.) The variance ratio is the ratio of the variance between cluster centroids to the mean, weighted intracluster variance. See text for details.