Which of the following is NOT a type of clustering?  Answer areaHierarchical clusteringDensity-based clusteringAgglomerative clusteringDecision tree clustering

To identify which of the options is NOT a type of clustering, let's analyze the options provided:

1. Hierarchical clustering: This is a method of cluster analysis that seeks to build a hierarchy of clusters.

2. Density-based clustering: This approach groups together points that are closely packed together, marking as outliers points that lie alone in low-density regions.

3. Agglomerative clustering: A specific type of hierarchical clustering that starts with individual points and merges them into larger clusters.

4. Decision tree clustering: This is not a clustering method. Decision trees are used for classification and regression problems, not for clustering.

Final Answer

Decision tree clustering is NOT a type of clustering.