K-Means Clustering Example with K=2
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Questions and Answers

Which of the following statements about K-means clustering is true?

  • It may get stuck in local optima. (correct)
  • It does not require specifying the number of clusters in advance.
  • It guarantees finding the optimal solution.
  • It works well on categorical data.
  • What is a common approach to mitigate the issue of local optima in K-means clustering?

  • Increase the number of clusters.
  • Use a different clustering algorithm.
  • Scale the data before clustering.
  • Repeat K-means with different initial cluster centers. (correct)
  • Which of the following is a strength of K-means clustering?

  • It does not require specifying the number of clusters.
  • It can handle categorical data.
  • It always finds the global optimum.
  • It is easy to use and understand. (correct)
  • What is a potential disadvantage of K-means clustering?

    <p>It is sensitive to outliers.</p> Signup and view all the answers

    Which of the following statements about K-means clustering is false?

    <p>It can handle categorical data.</p> Signup and view all the answers

    What is the primary difference between K-means clustering and hierarchical clustering?

    <p>K-means requires specifying the number of clusters, while hierarchical clustering does not.</p> Signup and view all the answers

    What is the primary objective of the K-Means Clustering algorithm?

    <p>To partition the observations into a pre-specified number of clusters</p> Signup and view all the answers

    In the initial step of the K-Means Clustering algorithm, how are the cluster centers (centroids) chosen?

    <p>They are randomly assigned from the feature space</p> Signup and view all the answers

    What is the criterion used to assign observations to clusters in the K-Means Clustering algorithm?

    <p>Euclidean distance</p> Signup and view all the answers

    What condition is used to determine the stopping criterion for the K-Means Clustering algorithm?

    <p>When the cluster centers no longer move or move within a specified threshold</p> Signup and view all the answers

    In the K-Means Clustering algorithm, what property must the cluster sets $C_1, C_2, ..., C_k$ satisfy?

    <p>$C_1 \cup C_2 \cup ... \cup C_k = {1, ..., n}$, where each observation belongs to one of the K clusters</p> Signup and view all the answers

    What is the primary disadvantage of the K-Means Clustering algorithm?

    <p>It is sensitive to the initial choice of cluster centers</p> Signup and view all the answers

    What is the fundamental principle behind K-Means clustering?

    <p>Minimizing the within-cluster variation</p> Signup and view all the answers

    What is the optimization problem that K-Means clustering aims to solve?

    <p>Minimize $\sum_{k=1}^K \sum_{x \in C_k} ||x - \mu_k||^2$</p> Signup and view all the answers

    Which statement about the clusters in K-Means clustering is true?

    <p>The clusters are always disjoint</p> Signup and view all the answers

    How is the within-cluster variation for a cluster $C_k$ defined in K-Means clustering?

    <p>$W(C_k) = \sum_{x \in C_k} ||x - \mu_k||^2$</p> Signup and view all the answers

    What is a potential weakness of K-Means clustering mentioned in the text?

    <p>It is difficult to choose the correct value of K</p> Signup and view all the answers

    Which statement about the strengths of K-Means clustering is true?

    <p>It is a simple iterative method where the user provides the number of clusters</p> Signup and view all the answers

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