RMSSTD Statement

The CLUSTER Procedure

RMSSTD Statement

RMSSTD variable ;

If the coordinates in the DATA= data set represent cluster means (for example, formed by the FASTCLUS procedure), you can obtain accurate statistics in the cluster histories for METHOD=AVERAGE, METHOD=CENTROID, or METHOD=WARD if the data set contains

a variable giving the number of original observations in each cluster (see the discussion of the FREQ statement earlier in this chapter)
a variable giving the root-mean-square standard deviation of each cluster

Specify the name of the variable containing root-mean-square standard deviations in the RMSSTD statement. If you specify the RMSSTD statement, you must also specify a FREQ statement.

If you omit the RMSSTD statement but the DATA= data set contains a variable called _RMSSTD_, then root-mean-square standard deviations are obtained from the _RMSSTD_ variable.

An RMSSTD statement or _RMSSTD_ variable is required when you specify the HYBRID option.

A data set created by FASTCLUS using the MEAN= option contains _FREQ_ and _RMSSTD_ variables, so you do not have to use FREQ and RMSSTD statements when using such a data set as input to the CLUSTER procedure.

Chapter Contents
Previous
Next
Top