Use the radio buttons to select the clustering method used for joining the clusters. The Fast Ward method is selected by default.
Choose this method to set the distance between clusters to the average distance between pairs of observations .This method tends to join clusters with small variances and is biased toward producing clusters with the same variance. ^{ 1 } Choose this method to set the distance between clusters to the squared Euclidean Distance between the means of each cluster. ^{ 2 } Choose this method to set the distance between clusters to the maximum distance between an observation in one cluster and an observation in the other. 2 Choose this method to apply Wardâ€™s minimum variable method more quickly for large numbers of rows. 2 Choose this method to set the distance between clusters to the ANOVA sum of squares between the two clusters summed over all the variables. At each generation, two clusters from the previous generation are merged to reduce the within-cluster sum of squares over all partitions. The sums of squares are easier to interpret when they are divided by the total sum of squares to give the proportions of variance (squared semipartial correlations).This method joins clusters to maximize the likelihood at each level of the hierarchy under the assumptions of multivariate normal mixtures, spherical covariance matrices, and equal sampling probabilities.
Sokal, R.R., and C.D. Michener. (1958) A statistical method for evaluating systematic relationships. University of Kansas Science Bulletin 38: 1409-1438.
Milligan, G.W. (1980) An examination of the effect of six types of error perturbation on fifteen clustering algorithms. Psychometrika 45: 325-342.