Arithmetic mean and standard deviation of a certain normal

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Arithmetic mean and standard deviation of a certain normal [#permalink]

02 Nov 2010, 05:32

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Arithmetic mean and standard deviation of a certain normal distribution are 13.5 and 1.5. What value is exactly 2 standard deviations less than the mean?
(A) 10.5
(B) 11
(C) 11.5
(D) 12
(E) 12.5

[Reveal] Spoiler: OA

Last edited by Bunuel on 19 Feb 2012, 22:25, edited 1 time in total.

Edited the question

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Re: the arthimetic and standard deviation [#permalink]

02 Nov 2010, 05:49

Original question is:

Arithmetic mean and standard deviation of a certain normal distribution are 13.5 and 1.5. What value is exactly 2 standard deviations less than the mean?
(A) 10.5
(B) 11
(C) 11.5
(D) 12
(E) 12.5

The value which is exactly two SD below the mean is: mean-2*SD=13.5-2*1.5=10.5.

Answer: A.
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Manager

Joined: 10 Sep 2010

Posts: 133

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Re: the arthimetic and standard deviation [#permalink]

02 Nov 2010, 14:32

Is this question really a 600-700 level?
What is the source?
Thanks

Re: the arthimetic and standard deviation [#permalink] 02 Nov 2010, 14:32

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Arithmetic mean and standard deviation of a certain normal

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Arithmetic mean and standard deviation of a certain normal

Arithmetic mean and standard deviation of a certain normal

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