Multiple Choice Questions on Hierarchical Clustering

📚 Quick Study Guide

🔍 Hierarchical clustering builds a hierarchy of clusters, from single data points to one all-encompassing cluster. 🌳 There are two main approaches: Agglomerative (bottom-up) and Divisive (top-down). 📈 Agglomerative clustering starts with each data point as a single cluster and iteratively merges the closest clusters. ✂️ Divisive clustering starts with one cluster containing all data points and recursively splits the cluster into smaller clusters. 📏 Common linkage methods include: Single, Complete, Average, and Ward. 📐 Single Linkage: Minimum distance between points in two clusters. 🧮 Complete Linkage: Maximum distance between points in two clusters. 📊 Average Linkage: Average distance between points in two clusters. ➕ Ward's Method: Minimizes the variance within clusters. 📉 The result is typically visualized using a dendrogram, a tree-like diagram showing the hierarchy of clusters.

Practice Quiz

1. Which of the following is NOT a type of linkage method used in hierarchical clustering?
   1. Single
   2. Complete
   3. Average
   4. Median
2. In agglomerative hierarchical clustering, what is the initial state?
   1. All data points belong to the same cluster.
   2. Each data point is in its own cluster.
   3. Data points are randomly assigned to clusters.
   4. A predefined number of clusters are formed.
3. What does a dendrogram represent in hierarchical clustering?
   1. A scatter plot of the data points.
   2. The hierarchy of clusters.
   3. A table of cluster sizes.
   4. A visualization of the data's correlation matrix.
4. Which linkage method minimizes the variance within clusters?
   1. Single
   2. Complete
   3. Average
   4. Ward
5. What is the primary difference between agglomerative and divisive hierarchical clustering?
   1. Agglomerative is top-down, divisive is bottom-up.
   2. Agglomerative starts with one cluster, divisive starts with many.
   3. Agglomerative only works with numerical data.
   4. Divisive only works with categorical data.
6. Which linkage method uses the maximum distance between points in two different clusters?
   1. Single
   2. Complete
   3. Average
   4. Ward
7. Which of the following is a disadvantage of hierarchical clustering?
   1. It is not suitable for large datasets.
   2. It always finds the optimal clustering.
   3. It requires specifying the number of clusters beforehand.
   4. It is not affected by noise in the data.