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# PS - Statistics

Author Message
Manager
Joined: 12 Apr 2006
Posts: 210
Location: India

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01 May 2009, 06:32
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

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I got this question correct but still not sure whether the way I solved is correct or not. So please explain the method with which you will solve this. TIA
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Senior Manager
Joined: 08 Jan 2009
Posts: 317

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01 May 2009, 08:23
Mean = 21 hours
SD = 6
One or Two SD below mean is

Mean - 1 ( SD ) = 21 -6 = 15
Mean - 2 ( SD) = 21 - 12 = 9

9 < n < 15

Ans n =12
Manager
Joined: 19 Aug 2006
Posts: 233

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02 May 2009, 17:05
I also got D, same calculations as above.
Re: PS - Statistics   [#permalink] 02 May 2009, 17:05
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# PS - Statistics

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