
Statistics for Data Science II End Term: 13 April 2025, Set QDD3 (January 2025 term)
The IIT Madras BS Statistics for Data Science II (Stats 2) End Term paper sat on 13 Apr 2025, in the January 2025 term, set QDD3: 15 questions for 40 marks in 180 minutes. Every question is below with its answer. Take it as a timed mock test to be marked, or read it through first.
- 15
- 40
- 180 min
- 9
- 1
- 5
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Correct answer
Question 2
Gamma (145, 12)
Gamma (12, 145)
Gamma (145, 72)
Gamma (72, 145)
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Correct answer
Gamma (145, 72)
Question 3
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Question 4
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Correct answers
Question 5
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Correct answer: 0.25 (accepted within ±0.03)
Question 6
The joint density function of two continuous random variables X and Y is given as:
Based on the above data, answer the given subquestions.
Find the marginal probability density function of X.
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Question 7
The joint density function of two continuous random variables X and Y is given as:
Based on the above data, answer the given subquestions.
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Correct answer: 0.33 (accepted within ±0.03)
Question 8
A factory produces electronic processors and their performance score depends on two factors: (i) Number of Cores (X), (ii) Cache Size (Y ). For a randomly chosen processor, the probability mass functions (PMFs) of X and Y are given as follows:
The overall performance score (Z) of a processor is defined as Z= 4X + 3Y .
Based on the above data, answer the given subquestions.
Identify all the possible values of overall performance score (Z).
{10, 13, 14, 16, 17, 20}
{11, 13, 19, 14, 18, 25}
{10, 11, 14, 16, 19, 20}
{11, 14, 15, 18, 19, 22}
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Correct answer
{11, 14, 15, 18, 19, 22}
Question 9
A factory produces electronic processors and their performance score depends on two factors: (i) Number of Cores (X), (ii) Cache Size (Y ). For a randomly chosen processor, the probability mass functions (PMFs) of X and Y are given as follows:
The overall performance score (Z) of a processor is defined as Z= 4X + 3Y .
Based on the above data, answer the given subquestions.
Compute the value of E [ Z ]. Enter the answer correct to one decimal place.
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Correct answer: 16.2 (accepted within ±0.2)
Question 10
Based on the above data, answer the given subquestions.
Find the maximum likelihood estimate of λ for the given sample. Enter the answer correct to two decimal places.
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Correct answer: 0.93 (accepted within ±0.03)
Question 11
Based on the above data, answer the given subquestions.
Assume the prior distribution of λ to be Gamma(2,2). Determine the posterior distribution of λ.
Gamma(7, 7.4)
Gamma(6.4, 7)
Gamma(7, 6.4)
Gamma(7.4, 7)
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Correct answer
Gamma(7, 7.4)
Question 12
Based on the above data, answer the given subquestions.
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Correct answer
Question 13
Based on the above data, answer the given subquestions.
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Correct answer: 2.67 (accepted within ±0.03)
Question 14
Based on the above data, answer the given subquestions.
State the null and alternative hypotheses.
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Question 15
Based on the above data, answer the given subquestions.
Suppose the researcher decides to increase the sample size 64 to 100 while keeping the same rejection threshold. What will be effect on level of significance?
The significance level will increase from 0.05 to 0.09.
The significance level will be same.
The significance level will decrease from 0.09 to 0.01.
The significance level will decrease from 0.09 to 0.05.
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Correct answer
The significance level will decrease from 0.09 to 0.05.