clusters.md
In volker: High-Level Functions for Tabulating, Charting and Reporting Survey Data

clusters are added

Code
  cluster_tab(data, cls_item)
Output


  |item |       total| Cluster 1|  Cluster 2|
  |:----|-----------:|---------:|----------:|
  |1    | 15.7 (10.5)| 5.5 (3.0)| 25.0 (3.3)|
  |2    | 15.7 (10.5)| 5.5 (3.0)| 25.0 (3.3)|
  |n    |          21|        10|         11|


  |Cluster   |  n|    p|
  |:---------|--:|----:|
  |Cluster 1 | 10|  48%|
  |Cluster 2 | 11|  52%|
  |total     | 21| 100%|

  n=21.



  |Statistic                      | Value|
  |:------------------------------|-----:|
  |Within-Cluster Sum of Squares  |  3.53|
  |Between-Cluster Sum of Squares | 36.47|

  Within-Cluster Sum of Squares for Scree Plot

  |Clusters k |  WSS|
  |:----------|----:|
  |1          | 40.0|
  |2          |  3.5|
  |3          |  2.4|
  |4          |  2.2|
  |5          |  1.6|
  |6          |  0.4|
  |7          |  0.3|
  |8          |  0.3|
  |9          |  0.2|
  |10         |  0.2|

  Automatically selected k=2 by the elbow criterion.