Cluster Observationsoverview how to example data see also
Cluster ObservationsStat > Multivariate > Cluster Observations
Use clustering of observations to classify observations into groups when the groups are initially not known.
This procedure uses an agglomerative hierarchical method that begins with all observations being separate, each forming its own cluster. In the first step, the two observations closest together are joined. In the next step, either a third observation joins the first two, or two other observations join together into a different cluster. This process will continue until all clusters are joined into one, however this single cluster is not useful for classification purposes. Therefore you must decide how many groups are logical for your data and classify accordingly. See Determining the final cluster grouping for more information.
Variables or distance matrix: Enter either the columns containing measurement data or a stored distance matrix on which to perform the hierarchical clustering of observations.
Linkage Method: Choose the linkage method that will determine how the distance between two clusters is defined.
Distance Measure: Choose the distance measure to use if you selected columns as input variables.
Standardize variables: Check to convert all variables to a common scale by subtracting the means and dividing by the standard deviation before the distance matrix is calculated. This is a good idea if the variables are in different units and you wish to minimize the effect of scale differences. If you standardize, cluster centroids and distance measures are in standardized variable space.
Specify Final Partition by
Number of Clusters: Choose to determine the final partition by a specified number of clusters. Enter this number in the box. See Determining the final cluster grouping.
Similarity Level: Choose to determine the final partition by the specified level of similarity. Enter this value in the box. See Determining the final cluster grouping.
Show Dendrogram: Check to display the dendrogram or tree diagram, showing the amalgamation steps. Use <Customize> to change the default display of the dendrogram.