Using k-means cluster analysis, you initially grouped the customers into three clusters. However, this solution was not very satisfactory, so you reran the analysis with four clusters. These results were better, and from the final cluster centers, you saw that a potentially profitable "Internet" grouping was missed in the three-cluster solution.

This example underscores the exploratory nature of cluster analysis, since it is impossible to determine the "best" number of clusters until you have run the analyses and examined the solutions.