Which of the following is true about WCSS in clustering?

WCSS, or Within-Cluster Sum of Squares, is indeed a crucial concept in clustering analysis and relates specifically to the compactness of clusters. The main purpose of WCSS is to evaluate how tightly grouped the data points in a given cluster are around the centroid. It does this by calculating the sum of the squares of the distances between each data point in the cluster and the cluster's centroid. A lower WCSS value indicates that the points within clusters are closer to the centroid, suggesting that the clusters are more compact.

Understanding the compactness of clusters is essential in clustering techniques, such as k-means, as it helps assess the quality of the clusters formed. A goal in clustering is to have dense, well-separated clusters, and WCSS provides a quantitative measure to identify that characteristic.

While some other options refer to concepts related to clustering, they do not accurately explain what WCSS measures. For example, stating that it measures the average distance between points in a cluster doesn't encapsulate the squared distances aspect, nor does it represent the total compactness that WCSS provides. Additionally, WCSS is not used explicitly to determine the optimal number of clusters—though it can assist in methods like the elbow method, where changes in WCSS are evaluated as