Question 1
+4 marksOne or more correct optionsSelect all that apply.
- A
- B
- C
- D

The IIT Madras BS Machine Learning Techniques (MLT) End Term paper sat on 13 Sept 2026, in the May 2026 term, set S2: 18 questions for 47 marks in 180 minutes. Every question is below with its answer. Take it as a timed mock test to be marked, or read it through first.
Correct answers
Perceptron.
A decision tree using axis-aligned splits.
Gaussian Naïve Bayes in which the class-conditional feature variances differ between the two classes.
A support vector machine with a linear kernel.
A support vector machine with an RBF (Gaussian) kernel.
Correct answers
A decision tree using axis-aligned splits.
Gaussian Naïve Bayes in which the class-conditional feature variances differ between the two classes.
A support vector machine with an RBF (Gaussian) kernel.
Let
Correct answers
Correct answers
Consider the effect of each operation below on a model's bias and variance. Which of the following statements are correct?
Regularising the weights in a linear/logistic regression model increases bias and decreases variance.
Increasing the maximum depth of a decision tree increases bias and decreases variance.
Increasing the number of hidden units in a neural network decreases bias and increases variance.
Removing all the non-support-vectors from the training set of an SVM leaves both bias and variance unchanged.
Correct answers
Regularising the weights in a linear/logistic regression model increases bias and decreases variance.
Increasing the number of hidden units in a neural network decreases bias and increases variance.
Removing all the non-support-vectors from the training set of an SVM leaves both bias and variance unchanged.
Correct answer: 1.09 (accepted within ±0.01)
Correct answer: 180
Correct answer
(A figure from the original paper is missing from the source site.)
(A figure from the original paper is missing from the source site.)
(A figure from the original paper is missing from the source site.)
Correct answer
(A figure from the original paper is missing from the source site.)
Consider one-dimensional ridge regression with no bias term. Given
and
Correct answer: 0.2 (accepted within ±0.01)
For the covariance matrix
, compute the variance captured along the first principal component.
Correct answer
Correct answer
Correct answer
Consider a binary classification dataset in which the two classes are perfectly linearly separable. You are considering a Perceptron, Logistic Regression, and a Decision Tree. If the objective is to learn a linear decision boundary and no probability estimates are required, which of the following classifiers are appropriate choices?
Perceptron only
Logistic Regression only
Both Perceptron and Logistic Regression
Decision Tree only
Correct answer
Both Perceptron and Logistic Regression
Correct answer
Note: coordinates of x1 vector are intentionally not provided.
Correct answer: 2.72 (accepted within ±0.01)
Which of the following statements about entropy and information gain in decision-tree learning are correct?
If a feature splits a node into perfectly pure children, its information gain at that node equals the entropy of that node.
Information gain can be negative if a split increases impurity.
After a parent node is split into child nodes, no individual child node can have entropy greater than the parent node's entropy.
Correct answers
If a feature splits a node into perfectly pure children, its information gain at that node equals the entropy of that node.
Which of the following statements about bagging are correct?
Bagging reduces the variance of the ensemble's prediction.
Bagging substantially reduces the bias of the base learner.
Bagging tends to help most when the base learners are diverse (weakly correlated with one another).
Bagging tends to help most with high-variance, low-bias base learners such as deep, unpruned decision trees.
averaging all base learner reduces variance, if every base learner produces identical predictions.
Correct answers
Bagging reduces the variance of the ensemble's prediction.
Bagging tends to help most when the base learners are diverse (weakly correlated with one another).
Bagging tends to help most with high-variance, low-bias base learners such as deep, unpruned decision trees.