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Machine Learning

Unsupervised Learning

Interview questions on Unsupervised Learning.

20 questions

Dimensionality Reduction

Q1. Why do we need dimensionality reduction?

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Dimensionality Reduction

Q2. List down the two main approaches for dimensionality reduction?

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Dimensionality Reduction

Q3. What are some linear techniques of dimensionality reduction?

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Dimensionality Reduction

Q4. What is the benefit of using linear methods for dimensionality reduction?

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Dimensionality Reduction

Q5. What is the benefit of using linear methods for dimensionality reduction? (Part 2)

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Dimensionality Reduction

Q6. What are the drawbacks of using linear methods for dimensionality reduction?

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Dimensionality Reduction

Q7. What are the benefits of using nonlinear methods in dimensionality reduction?

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Dimensionality Reduction

Q8. What are some non-linear techniques of dimensionality reduction?

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Dimensionality Reduction

Q9. Eigen decomposition is a common factorization technique used for dimensionality reduction. Is the eigen decomposition of a matrix always unique?

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Dimensionality Reduction

Q10. Name some applications of eigenvalues and eigenvectors.

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Dimensionality Reduction

Q11. We want to do PCA on a dataset of multiple features in different ranges. For example, one is in the range $0-1$ and one is in the range $10 - 1000$. Will PCA work on this dataset?

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Dimensionality Reduction

Q12. Under what conditions can one apply eigen decomposition? What about SVD?

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  1. What is the relationship between SVD and eigen decomposition?
  2. What’s the relationship between PCA and SVD?

Dimensionality Reduction

Q13. How does $t-SNE$ (T-distributed Stochastic Neighbor Embedding) work? Why do we need it?

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Dimensionality Reduction

Q14. Is it good to use PCA as a feature selection method?

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Dimensionality Reduction

Q15. Is PCA a linear model or non-linear model?

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Dimensionality Reduction

Q16. What is the importance of eigenvalues and eigenvectors in PCA?

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Dimensionality Reduction

Q17. How do you decide the number of principal components to retain in PCA?

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Dimensionality Reduction

Q18. What is the difference between PCA and Linear Discriminant Analysis (LDA)?

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Dimensionality Reduction

Q20. Explain the concept of whitening in PCA.

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