3 a) Write down the K-means clustering algorithm 5 b) One of the challenges of a clustering algorithm such as that in 3(a) is to find the optimal number of clusters. One technique to determine the appropriate number of clusters relies on Silhouette analysis. k3 K-4 Cluster k=5 6 Cluster 0 0 -0.1 0.0 08 1.0 -0.1 0.0 02 04 0.6 Silhouette Coefficient 04 Silhouette Coefficient 08 10 8 The diagram above shows the Silhouette plots of clusters of sizes 3 - 6. Which cluster size would you prefer? Explain your reasoning clearly