Dear Ralph,between and within clusters sum of squares (if you want variances, you need to divide them by the appropriate constant!) add up to the overall sum of squares, so you can get the beween clusters ss by computing the overall ss (one possibility to get this is to run kmeans with k=1) and subtracting the within cluster ss from it.
Note, however, that the F-value cannot be interpreted in the usual way and is particulary not F-distributed when computed on clusters from k-means, because for F-distribution you'd need to assume that groups are determined independently of the data.
Hope this helps, Christian On Fri, 2 Jul 2010, Ralph Modjesch wrote:
Hi, I like to present the results from the clustering method k-means in terms of variances: within and between Cluster. The k-means object gives only the within cluster sum of squares by cluster, so the between variance part is missing,for calculation the following table, which I try to get. Number of | Variance within | Var between | Var total | F-value Cluster k | cluster | cluster | | =============================================================== 2 .......| 25,00 ..........| 75,00 ......| 100 ......| 1,5 3 .......| 45,00 ..........| 55,00 ......| 100 ......| 1,7 Is there any package/ function which will do that? -- Mit freundlichen Grüßen Ralph Modjesch ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
*** --- *** Christian Hennig University College London, Department of Statistical Science Gower St., London WC1E 6BT, phone +44 207 679 1698 chr...@stats.ucl.ac.uk, www.homepages.ucl.ac.uk/~ucakche
______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
