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Stats I · Discrete random variables

BSMA1002 · 24 questions · 60 marks · 6 papers

Answer key

Indian Institute of Technology Madras

BS Degree Programme · Examination & Study Paper

BSMA1002 · Statistics for Data Science I

Discrete random variables

Official Paper

Examination Instructions & Guidelines

Solve on notebook/paper first before checking solutions.
MCQ: Exactly 1 option is correct. Negative marking applies.
NAT: Numerical response. No negative marking.
Scientific calculator allowed for all calculations.
Official answer key is sealed at the end of this sheet.

End Term · 31 Aug 2025 (FN)End Term

Q1NAT3 Marks·Write the number
Key ↓
Your answer:
Read the passage below, then answer Q2–Q3
Based on the above data, answer the given subquestions.
Q2NAT2 Marks·Write the number
Asked 2 times Key ↓
Find the value of c such that X has a valid pmf. Enter the answer correct to one decimal place.
Your answer:
Q3NAT3 Marks·Write the number
Asked 4 times Key ↓
Find the value of Var(X). Enter the answer correct to two decimal places.
Your answer:
Read the passage below, then answer Q4–Q5
Based on the above data, answer the given subquestions.
Q4NAT2 Marks·Write the number
Key ↓
What is the probability that a randomly selected box contains at most 1 defective item? Enter the answer correct to one decimal place.
Your answer:
Q5NAT3 Marks·Write the number
Asked 5 times Key ↓
Your answer:

End Term · 31 Aug 2025 (AN)End Term

Q6MCQ2 Marks·Choose one option
Asked 3 times Key ↓
1. A0.6
2. B0.8
3. C0.2
4. D1
Q7NAT3 Marks·Write the number
Key ↓
Your answer:
Read the passage below, then answer Q8–Q9
Based on the above data, answer the given subquestions.
Q8MCQ1 Mark·Choose one option
Key ↓
Find the range of X.
1. A{20, 10, 30, 40}
2. B{−20, 10, 30, 40}
3. C{−20, 0, 10, 30, 40}
4. D{0, 10, 20, 30, 40}
Q9MCQ4 Marks·Choose one option
Key ↓
Find the PMF of X.
1. A
2. B
3. C
4. D
Read the passage below, then answer Q10–Q11
Based on the above data, answer the given subquestions.
Q10NAT3 Marks·Write the number
Key ↓
Find the value of a.
Your answer:
Q11NAT2 Marks·Write the number
Key ↓
Your answer:

End Term · 13 Apr 2025 (FN)End Term

Q12NAT2 Marks·Write the number
Asked 2 times Key ↓
Your answer:
Read the passage below, then answer Q13–Q14
Based on the above data, answer the given subquestions.
Q13NAT2 Marks·Write the number
Asked 2 times Key ↓
If the probability that the vendor sells exactly 2 items in a day is 0.30, then find the value of a. Enter the answer correct to two decimal places.
Your answer:
Q14NAT2 Marks·Write the number
Key ↓
What is the probability that the vendor sells at least 2 items in a day? Enter the answer correct to two decimal places.
Your answer:
Read the passage below, then answer Q15–Q16
Based on the above data, answer the given subquestions.
Q15NAT3 Marks·Write the number
Asked 5 times Key ↓
Your answer:
Q16MCQ2 Marks·Choose one option
Key ↓
1. A
2. B
3. C
4. D

End Term · 13 Apr 2025 (AN)End Term

Q17MCQ3 Marks·Choose one option
Asked 3 times Key ↓
1. A0.15
2. B0.25
3. C0.75
4. D0.10
Q18NAT2 Marks·Write the number
Asked 3 times Key ↓
Your answer:
Read the passage below, then answer Q19–Q20
The probability mass function of a discrete random variable X is given by,
Based on the above data, answer the given subquestions.
Q19MCQ2 Marks·Choose one option
Asked 5 times Key ↓
Find the value of E(6X − 2).
1. A1
2. B4
3. C6
4. D8
Q20NAT2 Marks·Write the number
Asked 4 times Key ↓
Find the value of V (3X − 4).
Your answer:

End Term · 22 Dec 2024 (FN)End Term

Read the passage below, then answer Q21–Q22
Based on the above data answer the given subquestions.
Q21MCQ4 Marks·Choose one option
Asked 5 times Key ↓
1. A15
2. B10
3. C20
4. D12
Q22NAT2 Marks·Write the number
Asked 4 times Key ↓
Your answer:

End Term · 22 Dec 2024 (AN)End Term

Read the passage below, then answer Q23–Q24
Based on the above data answer the given subquestions.
Q23MCQ4 Marks·Choose one option
Asked 5 times Key ↓
1. A15
2. B10
3. C20
4. D12
Q24NAT2 Marks·Write the number
Asked 4 times Key ↓
Your answer:

Official Key

Master Answer Key & Explanations

Official answer keys from IIT Madras BS past papers. Click any question to review.

Reveal Key

Q160

Q20.2

Q30.73 to 0.79

Q40.3

Q522

Q6B

Q71.65 to 1.69

Q8B

Q9D

Q106

Q110.75

Q123.64 to 3.7

Q130.43 to 0.47

Q140.53 to 0.57

Q1534

Q16B

Q17D

Q1835

Q19B

Q2018

Q21B

Q221.01 to 1.07

Q23B

Q241.01 to 1.07

Questions and answer keys are reproduced from the official IIT Madras BS papers. Topics and repeated question types are BTechi’s own grouping. BTechi is not affiliated with IIT Madras.