Consider the following four faces shown in Figure 8.7. Again, darkness or number of dots represents density. Lines are used only to distinguish regions and do not represent points.

(a) For each figure, could you use single link to find the patterns represented

by the nose, eyes, and mouth? Explain.

(b) For each figure, could you use K-means to find the patterns represented

by the nose, eyes, and mouth? Explain.

(c) What limitation does clustering have in detecting all the patterns formed

by the points in Figure 8.7(c)?

(a) Only for (b) and (d). For (b), the points in the nose, eyes, and mouth
are much closer together than the points between these areas. For (d)
there is only space between these regions.
(b) Only for (b) and (d). For (b), K-means would find the nose, eyes, and
mouth, but the lower density points would also be included. For (d), K- means would find the nose, eyes, and mouth straightforwardly as long
as the number of clusters was set to 4.
(c) Clustering techniques can only find patterns of points, not of empty
spaces.