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January 2025 term · Statistics for Data Science II · BSMA1004

Statistics for Data Science II Quiz 1: 23 February 2025 (January 2025 term)

The IIT Madras BS Statistics for Data Science II (Stats 2) Quiz 1 paper sat on 23 Feb 2025, in the January 2025 term: 17 questions for 40 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.

Questions
17
Marks
40
Duration
120 min
MCQ
8
Numerical
8
MSQ
1

Updated

Official paper: IIT M DIPLOMA AN EXAM QDD2 23 Feb 2025 · No negative marking.

Question 1

+3 marksOne correct option
  1. A
  2. B
  3. C
  4. D
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Correct answer

  • B

Question 2

+3 marksOne correct option
  1. A
  2. B
  3. C
  4. D
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Correct answer

  • C

Question 3

+3 marksNumerical answer

A call center analyst monitors the number of calls received at the centre daily. Let X denote the number of calls received in a day. Using Markov’s inequality, the analyst determines an upper bound of 0.48 on the probability of receiving more than 249 calls. Calculate the mean of X.

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Correct answer: 120

Question 4

+3 marksNumerical answer
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Correct answer: 0.5

Question 5

+1 markOne correct option

What is the value of p?

  1. A
  2. B
  3. C
  4. D
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Correct answer

  • D

Question 6

+2 marksNumerical answer

Find the expected amount of money to be gain. Enter the answer correct to two decimal places.

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Correct answer: 13.75 (accepted within ±0.03)

Question 7

+2 marksNumerical answer

Based on the above data, answer the given subquestions.

Find Var(W). Enter the answer correct to two decimal places.

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Correct answer: 2.92 (accepted within ±0.03)

Question 8

+3 marksNumerical answer

Based on the above data, answer the given subquestions.

What is the value of E(Z +W)? Enter the answer correct to two decimal places.

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Correct answer: 9.75 (accepted within ±0.03)

Question 9

+3 marksOne correct option

Based on the above data, answer the given subquestions.

Identify the correct joint PMF table of X and Y .

  1. A
  2. B
  3. C
  4. D
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Correct answer

  • B

Question 10

+2 marksOne correct option

Based on the above data, answer the given subquestions.

What is the marginal distribution of X?

  1. A
  2. B
  3. C
  4. D
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Correct answer

  • A

Question 11

+3 marksOne correct option

Let X and Y denote the number of customers arriving at two different service counters (Counter 1 and Counter 2) in a bank during a one-hour interval. The random variables X and Y follow Poisson distributions with mean arrival rates of 15 customers per hour at Counter 1 and 25 customers per hour at Counter 2, respectively. Assume that X and Y are independent.
Based on the above data, answer the given subquestions.

If Z represents the combined total number of customers arriving at both counters during a one- hour interval, then determine the PMF of Z.

  1. A
  2. B
  3. C
  4. D
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Correct answer

  • D

Question 12

+2 marksOne or more correct options

Let X and Y denote the number of customers arriving at two different service counters (Counter 1 and Counter 2) in a bank during a one-hour interval. The random variables X and Y follow Poisson distributions with mean arrival rates of 15 customers per hour at Counter 1 and 25 customers per hour at Counter 2, respectively. Assume that X and Y are independent.
Based on the above data, answer the given subquestions.

Which of the following option(s) is/are correct?

Select all that apply.

  1. A
  2. B
  3. C
  4. D
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Correct answers

  • A
  • D

Question 13

+1 markNumerical answer

Based on the above data, answer the given subquestions.

Find the value of a.

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Correct answer: 3

Question 14

+2 marksOne correct option

Based on the above data, answer the given subquestions.

What is the CDF of X?

  1. A
  2. B
  3. C
  4. D
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Correct answer

  • B

Question 15

+2 marksOne correct option

Based on the above data, answer the given subquestions.

What is the value of P(−4 < X ≤ 6)?

  1. A
  2. B
  3. C
  4. D
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Correct answer

  • B

Question 16

+2 marksNumerical answer

Based on the above data, answer the given subquestions.

Find the probability that the factory will produce at most 3 defective light bulbs in a batch of 5 light bulbs. Enter the answer correct to two decimal places.

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Correct answer: 0.93 (accepted within ±0.03)

Question 17

+3 marksNumerical answer

Based on the above data, answer the given subquestions.

Find the value of P(X ≤ 4 | X > 1).

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Correct answer: 1