- CFA Exams
- 2021 CFA Level I Exam
- Study Session 3. Quantitative Methods (2)
- Reading 10. Sampling and Estimation
- Subject 6. Confidence Intervals for the Population Mean

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**CFA Practice Question**

What assumption is made when calculating a confidence interval around the mean for a sample with less than 30 data points?

II. The population from which the sample was taken is normally distributed.

III. The sample standard deviation is equal to the population standard deviation.

I. The sample is normally distributed.

II. The population from which the sample was taken is normally distributed.

III. The sample standard deviation is equal to the population standard deviation.

Correct Answer: II

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**User Contributed Comments**
2

User |
Comment |
---|---|

MFTIOA |
If Nonnormal and small sample, then a confidence interval can't be constructed |

ashish100 |
Thanks MFTIOA! cool name! |