quick look at machine learning the invocation contrivedtest ( falseprints final result cluster with centroid contains cluster with centroid contains cluster with centroid contains and the invocation contrivedtest ( falseprints final result cluster with centroid cluster with centroid cluster with centroid cluster with centroid cluster with centroid cluster with centroid contains contains contains contains contains containsthe last clustering is the tightest fiti the clustering has the lowest dissimilarity does this mean that it is the "bestfitrecall that when we looked at linear regression in section we observed that by increasing the degree of the polynomial we got more complex model that provided tighter fit to the data we also observed that when we increased the degree of the polynomial we ran the risk of finding model with poor predictive value-because it overfit the data choosing the right value for is exactly analogous to choosing the right degree polynomial for linear regression by increasing kwe can decrease dissimilarityat the risk of overfitting (when is equal to the number of examples to be clusteredthe dissimilarity is zero!if we have some information about how the examples to be clustered were generatede chosen from distributionswe can use that information to choose absent such informationthere are variety of heuristic procedures for choosing going into them is beyond the scope of this book less contrived example different species of mammals have different eating habits some species ( elephants and beaverseat only plantsothers ( lions and tigerseat only meatand some ( pigs and humanseat anything they can get into their mouths the vegetarian species are called herbivoresthe meat eaters are called carnivoresand those species that eat both are called omnivores over the millenniaevolution (or some other mysterious processhas equipped species with teeth suitable for consumption of their preferred foods that raises the question of whether clustering mammals based on their dentition produces clusters that have some relation to their diets