INTRODUCTION TO MACHINE LEARNING Week 12

Session: JULY-DEC 2023

Course Name: Introduction to Machine Learning

Course Link: Click Here

These are Introduction to Machine Learning Week 12 Assignment 12 Answers


Q1. You want to make an RL agent for a game where 2 players compete to win (like Chess and Go). Which among the given would be the best approach for this?
Play against best human players
Iteratively play against the best (fixed) version of itself
Play against a supervised agent trained on demonstrations of best human players
Watch thousands of games being played and learn the patterns in an unsupervised manner

Answer: Iteratively play against the best (fixed) version of itself


Q2. Statement 1: Empirical error is always greater than generalisation error.
Statement 2: Training data and test data have different underlying(true) distributions.
Choose the correct option:

Statement 1 is true. Statement 2 is true. Statement 2 is the correct reason for statement 1.
Statement 1 is true. Statement 2 is true. Statement 2 is not the correct reason for statement 1.
Statement 1 is true. Statement 2 is false.
Both statements are false.

Answer: Both statements are false.


These are Introduction to Machine Learning Week 12 Assignment 12 Answers


Q3. The Chernoff-Hoeffding bound for a classifier h indicates how close the empirical error is to the generalized error as a function of the number of samples in the data set.
P(|ε(h)−ε^(h)|>γ)≤2e−2γ2m
You test it and find that increasing the number of samples does not give a more accurate estimate. What could be the problem?

Choice of γ is unsuitable
The mean is not from Bernoulli distribution.
Choice of hypothesis function is wrong
Samples are not i.i.d

Answer: C, D


These are Introduction to Machine Learning Week 12 Assignment 12 Answers


Q4. Let P(Ai)=2−i. Calculate the upper bound for P(⋃5i=1Ai) using union bound (rounded to 3 decimal places).
0.937
0.984
0.969
1

Answer: 0.969


These are Introduction to Machine Learning Week 12 Assignment 12 Answers


Q5. Statement A: Reinforcement learning is a type of unsupervised learning.
Statement B: Reinforcement learning does not have labels.

Both statements are true. Statement B is the correct explanation for statement A.
Both statements are true. Statement B is NOT the correct explanation for statement A.
Statement A is true. Statement B is false.
Statement A is false. Statement B is true.
Both statements are false.

Answer: Statement A is false. Statement B is true.


These are Introduction to Machine Learning Week 12 Assignment 12 Answers


Q6. What is a policy in reinforcement learning?
A mapping from states to actions
A mapping from states to rewards
A mapping from actions to rewards
A mapping from actions to next state

Answer: A mapping from states to actions


These are Introduction to Machine Learning Week 12 Assignment 12 Answers


Q7. Given 100 hypothesis functions, each trained with 106 samples, what is the lower bound on the probability that there does not exist a hypothesis function with error greater than 0.1?
1−200e−2⋅104
1−100e104
1−200e102
1−200e−2⋅102

Answer: d. 1−200e−2⋅102


These are Introduction to Machine Learning Week 12 Assignment 12 Answers

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Session: JAN-APR 2023

Course Name: Introduction to Machine Learning

Course Link: Click Here

These are Introduction to Machine Learning Week 12 Assignment 12 Answers


Q1. Which of the following measure best analyze the performance of a classifier?
a. Precision
b. Recall
c. Accuracy
d. Time complexity
e. Depends on the application

Answer: e. Depends on the application


Q2. As discussed in the lecture, most of the classifiers minimize the empirical risk. Which among the following is an exceptional case?
a. Perceptron learning algorithm
b. Artificial Neural Network
c. Support Vector Machines
d. both (a) and (b)
e. None of the above

Answer: c. Support Vector Machines


These are Introduction to Machine Learning Week 12 Assignment 12 Answers


Q3. What do you expect to happen to the variance component of the generalisation error of your model as the size of the training data set increases?
a. Increase in variance
b. Decrease in variance
c. No change in variance error

Answer: b. Decrease in variance


Q4. After completing Introduction to Machine Learning on NPTEL, you have landed a job as a Data Scientist at YumEll Solutions Inc. Your first assignment as a trainee is to learn a classifier given some data and present insights on it to your manager, who apparently doesn’t seem to have any knowledge on Machine Learning. Which of the following classification models would you pick to best explain the nature of the data and the underlying distribution to your manager?
a. Linear Models
b. Support Vector Machines
c. Decision Trees
d. Artificial Neural Networks

Answer: c. Decision Trees


These are Introduction to Machine Learning Week 12 Assignment 12 Answers


Q5. What happens when your model complexity (such as interaction terms in linear regression, order of polynomial in SVM, etc.) increases?
a. Model Bias increases
b. Model Bias decreases
c. Variance of the model increases
d. Variance of the model decreases

Answer: b, c


These are Introduction to Machine Learning Week 12 Assignment 12 Answers


Q6. Suppose we want an RL agent to learn to play the game of golf. For training purposes, we make use of a golf simulator program. Assume that the original reward distribution gives a reward of +10 when the golf ball is hit into the hole and -1 for all other transitions. To aid the agent’s learning process, we propose to give an additional reward of +3 whenever the ball is within a 1 metre radius of the hole. Is this additional reward a good idea or not? Why?

a. Yes. The additional reward will help speed-up learning.
b. Yes. Getting the ball to within a metre of the hole is like a sub-goal and hence, should be rewarded.
c. No. The additional reward may actually hinder learning.
d. No. It violates the idea that a goal must be outside the agent’s direct control.

Answer: c. No. The additional reward may actually hinder learning.


These are Introduction to Machine Learning Week 12 Assignment 12 Answers


Q7. You want to toss a fair coin a number of times and obtain the probability of getting heads by taking a simple average. What is the estimated number of times you’ll have to toss the coin to make sure that your estimated probability is within 10% of the actual probability, at least 90% of the time?
a. 400*ln(20)
b. 800ln(20)
c. 200*ln(20)

Answer: c. 200*ln(20)


These are Introduction to Machine Learning Week 12 Assignment 12 Answers


Q8. A new phone, E-Corp X1 has been announced and it is what you’ve been waiting for, all along. You decide to read the reviews before buying it. From past experiences, you’ve figured out that good reviews mean that the product is good 90% of the time and bad reviews mean that it is bad 70% of the time. Upon glancing through the reviews section, you find out that the X1 has been reviewed 1269 times and only 127 of them were bad reviews. What is the probability that, if you order the X1, it is a bad phone?
a. 0.1362
b. 0.160
c. 0.840
d. 0.773

Answer: b. 0.160


These are Introduction to Machine Learning Week 12 Assignment 12 Answers


Q9. You face a particularly challenging RL problem, where the reward distribution keeps changing with time. In order to gain maximum reward in this scenario, does it make sense to stop exploration or continue exploration?
a. Stop exploration
b. Continue exploration

Answer: b. Continue exploration


These are Introduction to Machine Learning Week 12 Assignment 12 Answers

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These are Introduction to Machine Learning Week 12 Assignment 12 Answers
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