
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.
- 17
- 40
- 120 min
- 8
- 8
- 1
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Correct answer
Question 2
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Question 3
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
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Correct answer: 0.5
Question 5
What is the value of p?
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Question 6
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
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
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
Based on the above data, answer the given subquestions.
Identify the correct joint PMF table of X and Y .
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Question 10
Based on the above data, answer the given subquestions.
What is the marginal distribution of X?
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Question 11
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.
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Question 12
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?
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Correct answers
Question 13
Based on the above data, answer the given subquestions.
Find the value of a.
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Correct answer: 3
Question 14
Based on the above data, answer the given subquestions.
What is the CDF of X?
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Question 15
Based on the above data, answer the given subquestions.
What is the value of P(−4 < X ≤ 6)?
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Question 16
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
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