CFA Institute CFA-Level-I Exam - Topic 3 Question 14 Discussion

Actual exam question for CFA Institute's CFA-Level-I exam

Question #: 14
Topic #: 3

A sample of size 600 is drawn from a population. The sample mean equals 329. The total width of the 99% confidence interval for the population mean is 893. The estimated population variance equals ________.

A6.7

B4.9

C6.3

D7.3

Show Suggested Answer

Suggested Answer: D

by Cathern at Mar 19, 2025, 06:11 AM

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Frank

5 months ago

Wait, how do we even calculate that?

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Nohemi

5 months ago

I think the variance is around 6.3.

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Karrie

5 months ago

The sample size is 600, that's pretty big!

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Stevie

6 months ago

Definitely going with option D, 7.3 seems right.

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Carma

6 months ago

Not sure about that confidence interval, seems off to me.

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Raymon

6 months ago

I'm a bit confused about the relationship between the width of the interval and the variance. I hope I can remember the right formula during the exam!

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Mauricio

6 months ago

This question feels similar to one we practiced in class, where we had to derive variance from the confidence interval width. I think it involves dividing by the sample size.

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Latrice

7 months ago

I think we need to use the formula for the confidence interval to find the standard error first, but I can't recall the exact steps.

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Gretchen

7 months ago

I remember something about confidence intervals, but I'm not sure how to calculate the variance from the width.

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Whitley

7 months ago

This looks straightforward. We just need to plug in the values we're given and do the math. I'm confident I can work through this step-by-step and arrive at the correct answer.

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Jerry

7 months ago

Wait, what? I'm lost. How do we get from the confidence interval information to the population variance? I need to review my notes on this type of problem.

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Samuel

7 months ago

I've got this! We can use the formula for the 99% confidence interval: sample mean +/- (t-value * standard error). Rearranging this, we can solve for the population variance.

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Francis

7 months ago

Hmm, I'm a bit confused on how to approach this. I know we need to use the formula for the confidence interval, but I'm not sure how to rearrange it to solve for the population variance.

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Dudley

8 months ago

Okay, let's think this through step-by-step. We have the sample size, sample mean, and the total width of the 99% confidence interval. We can use this information to calculate the population variance.

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