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# quiz12

Introduction to Machine Learning (IITM) - - Unit 2 - Week 0
1 of 3
https://onlinecourses.nptel.ac.in/noc19_cs53/unit?unit=5&assessment=118
There are n bins of which the k-th bin contains k − 1 blue balls and n − k red balls. You pick a bin at random and remove two balls at
random without
replacement. Find the probability that:
the second ball is red;
the second ball is red, given that the first is red
1/3, 2/3
1/2, 1/3
1/2, 2/3
1/3, 1/3
2) A medical company touts its new test for a certain genetic disorder. The false negative rate is small: if you have the
1 point
disorder, the probability that the test
returns a positive result is 0.999. The false positive rate is also small: if you do not have the disorder, the probability that the test
returns a positive result is only
0.005. Assume that 2% of the population has the disorder. If a person chosen uniformly from the population is tested and the
result comes back positive, what is
the probability that the person has the disorder?
0.803
0.976
0.02
0.204
3) In an experiment, n coins are tossed, with each one showing up heads with probability p independently of the others.
1 point
Each of the coins which shows up
heads is then tossed again. What is the probability of observing 5 heads in the second round of tosses, if we toss 15 coins in the
first round and p = 0.4?
(Hint: First find the mass function of the number of heads observed in the second round.)
0.372
0.055
0.0345
0.0488
4) Consider two random variables X and Y having joint density function
. Are X and Y 1 point
independent? Find the
covariance of X and Y.
Yes, 1/4
Yes, 1/2
No, 1/4
No, 1/2
5) An airline knows that 5 percent of the people making reservations on a certain flight will not show up. Consequently, their 1 point
policy is to sell 52 tickets for a
7/23/2019, 2:11 PM
Introduction to Machine Learning (IITM) - - Unit 2 - Week 0
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https://onlinecourses.nptel.ac.in/noc19_cs53/unit?unit=5&assessment=118
flight that can hold only 50 passengers. What is the probability that there will be a seat available for every passenger who shows
up?
0.5101
0.81
0.6308
0.7405
6) Let X have mass function
and let
. For what values of
1 point
is it the case that
?
7) Is the following a distribution function?
1 point
If so, give the corresponding density function. If not, mention why it is not a distribution function.
No, not a monotonic function
Yes,
No, not right continuous
Yes,
8) Can the value of a probability density function be greater than one? What about the cumu- lative distribution function?
1 point
PDF: yes, CDF: yes
PDF: yes, CDF: no
PDF: no, CDF: yes
PDF: no, CDF: no
9) You are given a biased coin with probability of seeing a head is p = 0.6 and probability of seeing a tail is q = 0.4. Suppose 1 point
you toss the coin 10 times,
what is the probability of you getting the head at most 2 times? Also, what is the probability of you getting the head for the first
time on your fourth attempt?
0.012, 0.038
0.054, 0.038
0.012, 0.064
0.054, 0.064
10) Let u be a
vector, such that
. Let I be the n x n identity matrix. The n x n matrix A is given by
1 point
, where k is a real constant. u itself
7/23/2019, 2:11 PM
Introduction to Machine Learning (IITM) - - Unit 2 - Week 0
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https://onlinecourses.nptel.ac.in/noc19_cs53/unit?unit=5&assessment=118
is an eigenvector of A, with eigenvalue −1. What is the value of k?
-2
-1
1
2
11) Which of the following are true for any
matrix A of real numbers?
1 point
Note : There can be more than one correct option.
The rowspace of A is the same as the columnspace of A T
The rowspace of A is the same as the rowspace of A T
The eigenvectors of AAT are the same as the eigenvectors of ATA
The eigenvalues of AAT are the same as the eigenvalues of AT A
12) The Singular Value Decomposition (SVD) of a matrix R is given by
. Consider an orthogonal matrix Q such that A 1 point
= QR. The SVD of A is given by
. Which of the following are true?
13) Let
be a row stochastic matrix - in other words, all elements are non-negative and the sum of elements in every
1 point
row is 1. Let b be an eigenvalue of
A. Which of the following is true?
|b| > 1
|b| <= 1
|b| >= 1
|b| < 1
14) Let
of
be a matrix of real numbers. The matrix
has an eigenvector x with eigenvalue b. Then the eigenvector y 1 point
which has eigenvalue b is
equal to
Cannot be described in terms of x
7/23/2019, 2:11 PM
Introduction to Machine Learning (IITM) - - Unit 3 - Week 1
1 of 3
https://onlinecourses.nptel.ac.in/noc19_cs53/unit?unit=10&assessment=119
Which of the following is a supervised learning problem?
Predicting the outcome of a cricket match as win or loss based on historical data.
Recommending a movie to an exisiting user on a website like IMdB based on the search history (including other users)
Predicting the gender of a person from his/her image. You are given the data of 1 Million images along the gender
Given the class labels of old news articles, predicting the class of a new news article from its content. Class of a news article can
be such as sports, politics, technology, etc
2) Which of the following are classification problems?
1 point
Predicting the temperature (in Celsius) of a room from other environmental features (such as atmospheric pressure, humidity etc)
Predicting if a cricket player is a batsman or bowler given his playing records.
Finding the shorter route between two existing routes between two points.
Predicting if a particular route between two points has traffic jam or not based on the travel time of vehicles
3) Which of the following is a regression task?
1 point
Predicting the monthly sales of a cloth store in rupees.
Predicting if a user would like to listen to a newly released song or not based on historical data.
Predicting the confirmation probability (in fraction) of your train ticket whose current status is waiting list based on historical data
Predicting if a patient has diabetes or not based on historical medical records.
4) Which of the following is an unsupervised task?
1 point
Grouping images of footwear and caps separately for a given set of images
Learning to play chess
Predicting if an edible item is sweet or spicy based on the information of the ingredients and their quantities.
all of the above
5) Which of the following is a categorical feature?
1 point
Number of legs of an animal
Number of hours you study in a day
Branch of an engineering student
Your weekly expenditure in rupees.
6) Let X and Y be a uniformly distributed random variable over the interval [0,4] and [0,3] respectively. If X and Y are
1 point
independent events, then compute the probability,
None of the above
7)
Let the trace and determinant of a matrix
be 4 and 3 respectively. The eigenvalues of A are
1 point
7/25/2019, 12:18 PM
Introduction to Machine Learning (IITM) - - Unit 3 - Week 1
2 of 3
,
https://onlinecourses.nptel.ac.in/noc19_cs53/unit?unit=10&assessment=119
,where
1,3
None of the above
Can not be computed as the entries of the matrix A are not given
8) What would be the ideal complexity of the curve which can be used for polynomial curve fitting for the data shown below. 1 point
(y-axis denotes the dependent variable)
Linear
Cubic
If there are N training samples, fit a (N − 1) th order polynomial for achieving minimum training error
9) Which of the following are true about bias and variance of overfitted and underfitted models?
1 point
Underfitted models have low bias
Underfitted models have high bias
Overfitted models have low variance
Overfitted models have high variance
10) What happens when your model complexity increases?
1 point
Model Bias increases
Model Bias decreases
Variance of the model increases
Variance of the model decreases
7/25/2019, 12:18 PM
Introduction to Machine Learning (IITM) - - Unit 3 - Week 1
3 of 3
https://onlinecourses.nptel.ac.in/noc19_cs53/unit?unit=10&assessment=119
7/25/2019, 12:18 PM
Arab people

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