- CFA Exams
- 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**

If the size of the sample being used increases, the width of a 0.95 confidence interval estimate for a population mean will ______.

A. become narrower

B. become wider

C. not change

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**User Contributed Comments**
2

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

danlan |
When size increase, t statistics becomes closer to z statistics |

mchu |
Since population variance is constant no matter how large the sample size is, as we increase N, sigma/N decrease, thus the width is narrower. |