Data Analytics with Python Week 3 NPTEL Assignment Answers 2025

NPTEL Data Analytics with Python Week 3 Assignment Answers 2024

1. Why one should not go for sampling?

Options:
a. It is less costly to administer than a census
b. The person authorising the study is comfortable with the sample.
c. Because the research process is sometimes destructive
d. None of the above

Answer :- d ✅
Explanation: All listed reasons (a–c) actually support the use of sampling. The question asks for why one should not use sampling, but none of the options are valid reasons against it. So, correct answer is None of the above.

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2. Stratified random sampling is a method of selecting a sample in which

Options:
a. the sample is first divided into strata
b. various strata are selected from the sample
c. The population is first divided into strata, and then random samples are drawn from each stratum
d. None of the above

Answer :- c ✅
Explanation: In stratified sampling, the population is divided into groups (strata), and then random samples are taken from each. This ensures better representation of different subgroups.

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3. If P = 0.35, what’s the probability that sample proportion (n=100) lies between 0.3 and 0.4?

Options:
a. 0.961
b. 0.827
c. 0.706
d. 0.53

Answer :- c
Explanation: This is a problem involving sampling distribution of proportions. With P = 0.35 and n = 100, the normal approximation gives approx. 0.706 probability for 0.3 ≤ p ≤ 0.4.

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4. Probability of getting 12 heads in 20 tosses of a fair coin

Options:
a. 0.120
b. 0.240
c. 0.280
d. 0.301

Answer :- a
Explanation: Use binomial distribution with n = 20, p = 0.5.
P(X = 12) = C(20,12) * (0.5)^12 * (0.5)^8 ≈ 0.120.

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5. Mr X randomly answers 90 MCQs (each with 1 correct out of 4). Probability he gets at least 10 correct?

Options:
a. 0.9997
b. 0.7894
c. 0
d. 0.001

Answer :- a
Explanation: Expected score = 90 × 0.25 = 22.5.
Probability of scoring at least 10 is very high, hence ≈ 0.9997.

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6. 10 items inspected, defect rate = 5%. Probability exactly 2 are defective?

Options:
a. 0.065
b. 0.075
c. 0.085
d. 0.095

Answer :- b
Explanation: Use binomial formula:
P(X=2) = C(10,2) × (0.05)^2 × (0.95)^8 ≈ 0.075

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7. Daily car sales (Poisson with λ = 2.5). Probability of 5 sales in a day?

Options:
a. 0.0668
b. 0.544
c. 0.082
d. 0.205

Answer :- a
Explanation: Poisson formula:
P(X=5) = (2.5^5 * e^-2.5) / 5! ≈ 0.0668

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8. Same scenario as Q7. Probability of 0 sales in a day?

Options:
a. 0.0668
b. 0.544
c. 0.082
d. 0.205

Answer :- c
Explanation: P(X=0) = (2.5^0 * e^-2.5) / 0! = e^-2.5 ≈ 0.082

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9. Same scenario. Probability of at most 2 sales in a day (X ≤ 2)?

Options:
a. 0.0668
b. 0.544
c. 0.082
d. 0.205

Answer :- b
Explanation:
P(X≤2) = P(0) + P(1) + P(2) ≈ 0.082 + 0.205 + 0.257 = 0.544

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10. Same scenario. Probability of selling exactly 1 car in a day?

Options:
a. 0.0668
b. 0.544
c. 0.082
d. 0.205

Answer :- d
Explanation:
P(X=1) = (2.5^1 * e^-2.5) / 1! ≈ 0.205