@BLOCK CENTER DATA FROM CH. 16 OF AFIFI & CLARK EXAMPLE WITH N=5 @END MIXPCMA CLUSPAC - MIXTURE-MODEL CLUSTERING OF CASES COMMON COVARIANCE MATRIX MODEL-SELECTION CRITERIA NUMBER MINUS 2 NUMBER (PPH=POST.PROB.OF MODEL): OF TIMES OF AKAIKE SCHWARZ CLUSTERS, LOG OF PARAM- ------------ ------------ K LIKELIHOOD ETERS VALUE PPH VALUE PPH --------- ---------- ----- ------- --- ------- --- 1 43.6 5 53.6 0.99 51.7 0.09 2 42.3 8 58.3 0.01 55.2 0.02 3 42.0 11 64.0 0.00 59.7 0.00 4 24.1 14 52.1 0.00 46.7 0.89 5 34.4 17 68.4 0.00 61.8 0.00 WITH K = 2, THE CLUSTERING WAS {1,2,3},{4,5} RATHER THAN THE OBVIOUSLY "CORRECT" {1,2},{3,4,5}. ................................................................. MIXPDTA CLUSPAC - MIXTURE-MODEL CLUSTERING OF CASES VARYING COVARIANCE MATRICES MODEL-SELECTION CRITERIA NUMBER MINUS 2 NUMBER (PPH=POST.PROB.OF MODEL): OF TIMES OF AKAIKE SCHWARZ CLUSTERS, LOG OF PARAM- ------------ ------------ K LIKELIHOOD ETERS VALUE PPH VALUE PPH --------- ---------- ----- ------- --- ------- --- 1 43.6 5 53.6 0.13 51.7 0.00 ==> 2 23.5 11 45.5 0.87 ==>41.2 0.97 3 26.5 17 60.5 0.00 53.8 0.03 4 32.7 23 78.7 0.00 69.7 0.00 5 43.6 29 101.6 0.00 90.3 0.00 WITH K = 2, THE CLUSTERING WAS THE OBVIOUSLY "CORRECT" {1,2},{3,4,5}. ................................................................. Performance of the default option of BMDPKM (Dixon 1990) on these data: (Afifi and Clark 1990, p. 445) The program starts with all cases in a single cluster. The program then searches for the variables with the highest variance, in this case the first variable. The original cluster is then split into two clusters, using the midrange of the first variable as the dividing point. After this every case already belongs to the cluster whose centroid is closest to it. Thus the algorithm stops, with the two clusters selected being clusters {1,2,3} and {4,5}. Dixon, W.J., ed. (1990). BMDP Statistical Software 1990. Vols. 1 and 2. Univ. of Calif. Press, Berkeley.