Question

Which among the following is not a valid distance specifying criterion between the clusters, in the context of hierarchical clustering?

• A. Single linkage
• B. Group Average
• C. Complete Linkage
• D. Double linkage

Hint:

In hierarchical clustering, the valid distance criteria include single linkage, group average, and complete linkage.

Answer 1

The Correct Option is D

Step 1: Understanding hierarchical clustering.
Hierarchical clustering measures the distance between clusters using criteria such as single linkage, group average, and complete linkage. Double linkage is not a valid criterion.

Step 2: Analysis of options.
- (A) Single linkage: Valid. This defines cluster distance as the minimum distance between elements in different clusters.
- (B) Group Average: Valid. This calculates the average distance between all points in different clusters.
- (C) Complete Linkage: Valid. This defines cluster distance as the maximum distance between elements in different clusters.
- (D) Double linkage: Invalid. Double linkage is not a recognized criterion in hierarchical clustering.

Step 3: Conclusion.
The incorrect option, and thus the correct answer to identify the invalid criterion, is (D) Double linkage.