Describe a method to evaluate the clusters.

Describe a method to evaluate the clusters.



The silhouette coefficient is a measure of the compactness and separation of the clusters. It increases as the quality of the clusters increase; it is large for compact clusters that are far from each other and small for large, overlapping clusters. The silhouette coefficient is calculated per instance; for a set of instances, it is calculated as the mean of the individual samples' scores. The silhouette coefficient for an instance is calculated with the following equation: s = (ba) / max(a,b)

a is the mean distance between the instances in the cluster. b is the mean distance between the instance and the instances in the next closest cluster.


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