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标题: Schweser Exam Quant Question [打印本页]

作者: Benjiko    时间: 2013-4-17 18:07     标题: Schweser Exam Quant Question

A security has annual return of 5%, 10%, 15%. The coefficient of variation for the security (using the population standard deviation) is closest to:
A. 0.3
B. 0.4
C. 0.5
D 0.6
My questions is: If it specifies to use the population standard deviation, why do we still have to divide by 3 when calculating the variance and not by 2?
The correct answer was B by the way, and it requires dividing the sum of squared deviations by 3, not by 2.
Thanks in advance
作者: king_kong    时间: 2013-4-17 18:07

if you’re finding the pop s dev, you divide by n and not n1.
it has something to do with allowing less error in the sample s dev if you use n1.
So, you get standard dev. of 4.0825, divide by the mean (10) and get .4
作者: skycfa    时间: 2013-4-17 18:07

Lol, oops, I read pop Stdev and my mind interpreted it as Sample Stdev…
Maybe I should take a study break




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