Perform agglomerative clustering on the accompanying data set. 

a. Include all five variables, first standardized to z-scores. Use the Euclidean distance for similarity and single linkage for the clustering method to cluster the data into three clusters. How many observations are in the largest cluster? What is the average value of x₄ of the largest cluster? 

b. Repeat part a but choose the complete linkage clustering method. 

c. Repeat part a but choose Ward’s clustering method