MS-DS Master of Data science FREE MS-DS Master of Data science Unsupervised Machine Learning Models Questions and Answers 2

Question 1

In DBSCAN, what is the role of the epsilon (eps) parameter?

Accepted Answer

It defines the maximum distance between two points to be considered neighbors

Answer

The epsilon parameter in DBSCAN defines the radius of the neighborhood around each point used to identify density-connected regions.

Question 2

Which technique is most appropriate for reducing high-dimensional data while preserving local neighborhood structure?

Accepted Answer

t-Distributed Stochastic Neighbor Embedding (t-SNE)

Answer

t-SNE is specifically designed to preserve local neighborhood relationships when projecting high-dimensional data into lower dimensions for visualization.

Question 3

What does the silhouette coefficient measure in cluster analysis?

Accepted Answer

How similar an object is to its own cluster compared to other clusters

Answer

The silhouette coefficient compares intra-cluster cohesion with inter-cluster separation, ranging from -1 to 1 where higher values indicate better-defined clusters.

Question 4

In Gaussian Mixture Models (GMM), what algorithm is typically used to estimate the model parameters?

Accepted Answer

Expectation-Maximization (EM)

Answer

The Expectation-Maximization algorithm iteratively estimates the posterior probabilities of cluster memberships (E-step) and updates the Gaussian parameters (M-step) until convergence.

Question 5

What is a key advantage of hierarchical agglomerative clustering over K-Means?

Accepted Answer

It does not require specifying the number of clusters in advance

Answer

Hierarchical agglomerative clustering builds a dendrogram that can be cut at any level, allowing the analyst to choose the number of clusters after the algorithm has run.

MS-DS Master of Data science Practice Test

MS-DS Master of Data science Practice Test

MS-DS Master of Data science FREE MS-DS Master of Data science Unsupervised Machine Learning Models Questions and Answers 2