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Stat 407 Quiz 2 Fall 2001 Name 1. (2pts) Which of the following linkage methods for hierarchical clustering is the most likely to give the following grouping of cases into cluster 1 and cluster 2? Explain. (a) Single , (b) Complete, (c) Wards (d) Average. 2. (2pts) On the above plot draw your guess at the solution that would be provided by k-means clustering, with k = 2. Explain. 3. (1pt) Fuzzy c-means is a variant of the k-means clustering algorithm. (T or F) 1 4. (2pts) From this formula for a bivariate normal density tell me what the mean is and the variance-covariance of the distribution is. f (x1 , x2 ) = 1 4 2 2π 2 5 1/2 1 × exp{− (x1 + 5 x2 − 2) 2 " 5/16 −1/8 −1/8 1/4 # x1 + 5 x2 − 2 ! } 5. (2pts) Which of the following is most likely not a sample from a normal distribution? Explain. 6. (1pt) Mahalanobis (or statistical) distance derives from the exponent of the multivariate normal density function. (T or F) 2