Question 1
Note: For numerical answer type questions, always enter your answer correct upto two decimal places without rounding up or off.

The IIT Madras BS Reinforcement Learning (Reinforcement Learning) Quiz 2 paper sat on 3 Dec 2023, in the September 2023 term: 21 questions for 50 marks in 120 minutes. Every question is below with its answer. Take it as a timed mock test to be marked, or read it through first.
Note: For numerical answer type questions, always enter your answer correct upto two decimal places without rounding up or off.
Correct answer: 10
Based on the above data, answer the given subquestions.
What is the estimate of V (B) returned by first-visit MC?
Note: For numerical answer type questions, always enter your answer correct upto two decimal places without rounding up or off.
Correct answer: 0.5 (accepted within ±0.05)
Based on the above data, answer the given subquestions.
What is the estimate of V (A) returned by first-visit MC?
Note: For numerical answer type questions, always enter your answer correct upto two decimal places without rounding up or off.
Correct answer: 0.975 (accepted within ±0.005)
Based on the above data, answer the given subquestions.
What is the estimate of V (B) returned by batch TD(0)?
Note: For numerical answer type questions, always enter your answer correct upto two decimal places without rounding up or off.
Correct answer: 0.5 (accepted within ±0.05)
Based on the above data, answer the given subquestions.
What is the estimate of V(A) returned by batch TD(0)?
Note: For numerical answer type questions, always enter your answer correct upto two decimal places without rounding up or off.
Correct answer: 1.2 (accepted within ±0.05)
Correct answer
Which of the following is correct update rule for expected SARSA:
Correct answer
Choose the correct option:
SARSA will have more maximization bias compared to Q-learning.
Q-learning will have more maximization bias compared to SARSA.
SARSA and Q-learning will have nearly the same maximization bias.
Maximization bias for SARSA and Q-learning can not be compared.
None of these.
Correct answer
Q-learning will have more maximization bias compared to SARSA.
Consider the following and select the correct option.
Assertion: Double Q learning removes or minimizes maximization bias.
Reason: The target action for Q1 is chosen from Q2 estimate and vice versa.
Assertion and Reason are both true and Reason is a correct explanation of Assertion
Assertion and Reason are both true and Reason is not a correct explanation of Assertion
Assertion is true and Reason is false
Both Assertion and Reason are false
Correct answer
Assertion is true and Reason is false
Identify the correct Q function estimated by Dueling DQN?
Correct answer
What is the advantage of computing n^(th) step reward vs 1-step reward?
Correct answers
Select correct statements regarding eligibility traces:
It is an approach to implement the T D(λ) algorithm.
The state closest to the terminal state in an episode, has the least value of eligibility trace.
It is initialized as 0 before every trajectory in the TD algorithm.
It is initialized as 0 at the beginning of the TD algorithm.
None of these.
Correct answers
It is an approach to implement the T D(λ) algorithm.
It is initialized as 0 before every trajectory in the TD algorithm.
Based on the above data, answer the given subquestions.
What are the Q values for all the actions (i.e. left, up, right, down in that order) in state s1?
[2, 5, 8, 11]
[2, 5, 11, 8]
[5, 2, 8, 11]
[11, 8, 2, 5]
None of these.
Correct answer
[2, 5, 8, 11]
Based on the above data, answer the given subquestions.
What is the TD(0) target (Q-learning) for this transition?
Note: For numerical answer type questions, always enter your answer correct upto two decimal places without rounding up or off.
Correct answer: 17
Based on the above data, answer the given subquestions.
Note: For numerical answer type questions, always enter your answer correct upto two decimal places without rounding up or off.
Correct answer: 8
Training a neural network with TD target, can diverge because:
High correlation between consecutive samples.
Target keeps moving as fast as the function approximator.
The target is moved towards the function approximator.
The features are learnt from scratch.
None of these.
Correct answers
High correlation between consecutive samples.
Target keeps moving as fast as the function approximator.
Suppose we are using a policy gradient method to solve a reinforcement learning problem. Assuming that the policy returned by the method is not optimal, which among the following are the plausible reasons for such an outcome?
The search procedure converged to a locally optimal policy.
The search procedure was terminated before it could reach an optimal policy.
An optimal policy could not be represented by the parameterisation used to represent the policy.
None of these
Correct answers
The search procedure converged to a locally optimal policy.
The search procedure was terminated before it could reach an optimal policy.
An optimal policy could not be represented by the parameterisation used to represent the policy.
What are the advantages of policy search methods over other approaches?
They can lead to simpler solution description.
They offer better convergence as compared to function approximation based methods.
In continuous action setting, they work better than value function based approaches.
They are robust to partial observability.
None of these.
Correct answers
They can lead to simpler solution description.
They offer better convergence as compared to function approximation based methods.
In continuous action setting, they work better than value function based approaches.
They are robust to partial observability.
Which of the problems does the replay buffer solve regarding training a Q-network?
High correlation between consecuteve samples.
Target keeps moving as fast as the function approximator.
The target is moved towards the function approximator.
None of these.
Correct answer
High correlation between consecuteve samples.
Which of the following is the correct way to represent policy for policy search methods? Assume θ represents a real valued parameter.
Correct answer
Which of the following is the correct way to represent policy for policy search methods?
Correct answer