What can be inferred from examining the cutoff line in a dendrogram?

In hierarchical clustering, a dendrogram is a visual representation of the data that displays the arrangement of the clusters formed by the clustering algorithm. The cutoff line across the dendrogram indicates where to cut the tree to define the clusters. By drawing a horizontal line across the dendrogram, you can determine how many clusters to form based on the height at which you cut. Each vertical line you intersect with the cutoff line corresponds to a different cluster.

Choosing the ideal number of clusters is essential because it directly influences the quality and applicability of the clustering outcomes in data analysis. Therefore, the information gleaned from examining the cutoff line in a dendrogram is critical for making informed decisions about the structure of the data when clustering is involved.