the nuts and bolts of machine learning coursera week 3 quiz answers
Test your knowledge: Explore unsupervised learning and K-means
1. Fill in the blank: K-means is an unsupervised partitioning algorithm used to organize _____ data into clusters.
- unlabeled
- presorted
- subcategorized
- hierarchical
2. In k-means, what term describes the point at which each cluster is defined?
- Commonality
- Centroid
- Core
- Coordinate
3. A data professional is iterating on certain tasks that will enable them to create a k-means model. They continue doing this until the algorithm converges. Which step of the model-building process does this scenario represent?
- Step four
- Step three
- Step two
- Step one
Test your knowledge: Evaluate a K-means model
4. In a k-means model, which evaluation metric represents the sum of the squared distances between each observation and its closest centroid?
- Silhouette score
- SMAPE
- F1-score
- Inertia
Test your knowledge: Evaluate a K-means model
5. In a k-means model, which evaluation metric represents the sum of the squared distances between each observation and its closest centroid?
- Silhouette score
- SMAPE
- F1-score
- Inertia
6. Fill in the blank: A data professional may use the _____ method to choose an optimal value for k. This is a tool for identifying the point at which the decrease in inertia starts to level off.
- partitioning
- elbow
- clustering
- unsupervised learning
7. A data professional is using Scikit-learn to create a k-means model. Which attribute will enable them to get the cluster assignments?
- Inertia
- Labels
- Fit
- Silhouette score
Weekly challenge 3
8. Which of the following statements correctly describe key aspects of k-means? Select all that apply.
- K-means is an unsupervised partitioning algorithm.
- The value of k is a standard that never changes.
- K-means clusters are defined by a central point, called a centroid.
- To avoid poor clustering, data professionals run a k-means model with different starting positions for the centroids.
Shuffle Q/A 1
9. A data professional is recalculating the centroid of each cluster. Which step of the model-creation process are they working in?
- Step four
- Step one
- Step three
- Step two
10. Fill in the blank: In order to evaluate the intracluster space in a k-means model, a data professional uses the inertia metric. This is the _____ of the squared distances between each observation and its nearest centroid.
- difference
- sum
- average
- ratio