NPTEL IITKGP Introduction to Machine Learning Assignment 7 Answers

1.Which of the following option is/ are correct regarding the benetfits of ensemble model?

1. Better performance
2. More generalized model
3. Better interpretability

A) 1 and 3
B) 2 and 3
C)1 and 2
D) 1, 2 and 3

Answer:- c
2. In AdaBoost, we give more weights to ponts having been misclassified in previous iterations. Now, if we introduced a limit or cap on the weight that any point can take (for example, say we introduce a restriction that prevents any point’s weight from exceeding a value of 10). Which among the following would be an effect of such a modification?

A) We nmay observe the performance of the classıfier reduce as the number of stagesincrease.
B) It makes the final classifier robust to outliers.
C) It may result in lower overall performance.
D) None of these.

Answer:- b, c

Introduction To Machine Learning – IITKGP Assignment 7 Answers 2022
3. Which among the following are some of the differences between bagging and boosting?

A) In bagging we use the same classification algorithm for training on each sample of the data, whereas in boosting, we use different classification algorithms on the different training data samples.
B) Bagging 1s easy to parallelize whereas boosting 1s inherently a sequential process.
C) In bagging we typically use sampling with replacement whereas in boosting, we typically use weighted sampling techniques.
D) In comparison with the performance of a base classifier on a particular dataset, bagging will generally not increase the error whereas as boosting may leadto an increase in the error.

Answer:- b, c, d
4. What is the VC-dimension of the class of sphere in a 3-dimensional plane?

A) 3
B) 4
C) 5
D) 6

Answer:- a
5. Considering the AdaBoost algorithm, which among the following statements is true?

A)In each stage, we try to train a classifier which makes accurate predictions on anysubset of the data points where the subset size is at least half the size of the data et.
B) In each stage, we try to tran a classifier which makes accurate predictions on a subset of the data points where the subset contains more of the data points whichwere misclassified in earlier stages.
C) The weight assigned to an undividual classifier depends upon the number of data points correctly classified by the classifier.
D) The weight assigned to an individual classifier depends upon the weighted sumerror of misclassified ponts for that classifier.

Answer:- b, d
6. Suppose the VC dimension of a hypothesis space is 6. Which of the following are true?

A) At least one set of 6 points can be shattered by the hypothesis space.
B) Two sets of 6 points can be shattered by the hypothesis space.
C) All sets of 6 points can be shattered by the hypothesis space.
D) No set of 7 points can be shattered by the hypothesis space.

Answer:- a, d

Introduction To Machine Learning – IITKGP Assignment 7 Answers 2022

7. Ensembles will yield bad results when there is a sıgnificant diversıty among the models. Write True or False.

A) True
B) False

Answer:- b
8. Which of the following algorithms are not an ensemble learning algorithm?

A) Random Forest
B) Adaboost
C) Gradient Boosting
D) Decision Tress

Answer:- d
9. Which of the following can be true for selecting base learners for an ensemble?

A) Different learners can come from same algorithm with different hyper parameters
B) Different learmers can come firom different algorithms
C)Different learners can come from different training spaces
D) All of the above.

Answer:- d

10. Generally, an ensemble method works better, if the indıvidual base models have____________?

Note: Indvidual models have accuracy greater than 50%

A) Less corelation among predictions
B) High correlation among predictions
C) Correlation does not have an impact on the ensemble output
D) None of the above.

Answer:- a