2. Now, we will use K-means and hierarchical clustering on the data. (a) How many clusters do you think we should specify? Why? (b) Conduct K-means clustering with 2 clusters. What are the cluster means? (Hint, In R, set.seed(1) km.out = kmeans(tumor,2,nstart=20) (c) Make a scatterplot matrix between all variables and color the points by cluster. Describe your findings. (Hint. In R, pairs(tumor,col=km.out$cluster)) (d) Using complete linkage, perform hierarchical clustering and color the points on the scatterplot matrix as in the previous question. Is the result much different? (Hint: In R, hc.complete=hclust(dist(tumor), method="complete") cutree(hc.comp|ete,2)