Machine Learning Questions & Answers
11. Which of the following is a widely used and effective machine learning algorithm based on the idea of bagging?
Explanation: The Radom Forest algorithm builds an ensemble of Decision Trees, mostly trained with the bagging method.
12. To find the minimum or the maximum of a function, we set the gradient to zero because:
Explanation: The gradient of a multivariable function at a maximum point will be the zero vector of the function, which is the single greatest value that the function can achieve.
13. Which of the following is a disadvantage of decision trees?
Explanation: Allowing a decision tree to split to a granular degree makes decision trees prone to learning every point extremely well to the point of perfect classification that is overfitting.
14. How do you handle missing or corrupted data in a dataset?
Explanation: All of the above techniques are different ways of imputing the missing values.
15. When performing regression or classification, which of the following is the correct way to preprocess the data?
Explanation: You need to always normalize the data first. If not, PCA or other techniques that are used to reduce dimensions will give different results.
16. Which of the following statements about regularization is not correct?
Explanation: A large value results in a large regularization penalty and therefore, a strong preference for simpler models, which can underfit the data.
17. Which of the following techniques can not be used for normalization in text mining?
Explanation: Lemmatization and stemming are the techniques of keyword normalization.
18. In which of the following cases will K-means clustering fail to give good results?
1) Data points with outliers
2) Data points with different densities
3) Data points with nonconvex shapes
Explanation: K-means clustering algorithm fails to give good results when the data contains outliers, the density spread of data points across the data space is different, and the data points follow nonconvex shapes.
19. Which of the following is a reasonable way to select the number of principal components "k"?
Explanation: This will maintain the structure of the data and also reduce its dimension.
20. What is a sentence parser typically used for?
Explanation: Sentence parsers analyze a sentence and automatically build a syntax tree.