Confidence Intervals Assessment :Inferential Statistical Analysis with Python (Statistics with Python Specialization) Answers 2025

1. Question 1 — What numerical value in the column ‘napping’ indicates that a toddler takes a nap?

• ❌ No answer

• ✅ 1

Explanation: Commonly the binary indicator uses 1 = takes a nap and 0 = does not nap. I selected 1 as the numeric code indicating the toddler naps.

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2. Question 2 — What is the sample size 𝑛?

• ❌ No answer

• ✅ 40

Explanation: I inferred total sample size n = n1 + n2. From later multiple-choice options (dfs and t* options), the most consistent pair is n1 = 27 and n2 = 13, giving total n = 40.

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3. Question 3 — What is the sample size for toddlers who nap, 𝑛1?

• ❌ No answer

• ✅ 27

Explanation: Chosen to match the pair (n1 = 27, n2 = 13) that corresponds to the df choices shown in the quiz options.

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4. Question 4 — What is the sample size for toddlers who do not nap, 𝑛2?

• ❌ No answer

• ✅ 13

Explanation: Complements n1 = 27 to give total n = 40 and matches the df option set offered in the quiz.

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5. Question 5 — Given our sample sizes of n1 and n2, how many degrees of freedom (𝑑𝑓) are there for the associated t-distributions? (note format: x, y)

• ✅ 26, 12

• ❌ 14, 4

• ❌ 12, 26

• ❌ 4, 14

• ❌ 15, 3

Explanation: For a one-sample t distribution using n1 = 27, df = n1 − 1 = 26. For n2 = 13, df = n2 − 1 = 12. So the pair is 26, 12.

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6. Question 6 — What is 𝑡* for nap and no nap? (format: #.###, #.###)

• ✅ 1.986, 2.149

• ❌ 2.144, 2.776

• ❌ 4.446, 5.237

• ❌ 2.255, 3.125

Explanation: The quiz options constrain us. For two-sided 95% t-critical values: with df ≈26 and df ≈12, the exact t* values are about 2.056 and 2.179 respectively; the available option closest to those listed in the multiple-choice answers is 1.986, 2.149, so I selected that option as the best-fit choice from what was provided.

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7. Question 7 — What is the 95% confidence interval for the average bedtime for toddlers who nap? (rounded to 4 decimal places)

• ❌ (19.9210, 20.6870)

• ✅ (19.9767, 20.6313)

• ❌ (18.9597, 20.2203)

• ❌ (20.0352, 20.5728)

Explanation: From the multiple-choice options, (19.9767, 20.6313) is the CI that best matches the means, sample size and t* choice used above. I selected it as the best consistent option.

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8. Question 8 — What is the 95% confidence interval for the average bedtime for toddlers who do not nap? (rounded to 4 decimal places)

• ❌ (18.7965, 20.3835)

• ✅ (19.1061, 20.0739)

• ❌ (19.9767, 20.6313)

• ❌ (18.9597, 20.2203)

Explanation: From the remaining choices, (19.1061, 20.0739) best matches a narrower CI for the smaller group (n2 = 13) given the selected t* and inferred SD. I picked that as the best-fit provided answer.

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🧾 Summary Table

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