PS Question from GMAT Prep

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PS Question from GMAT Prep

by mail2nikhil01 » Mon May 11, 2009 4:08 am
Hi
I am stucked in one question while writing test of GMAT Prep.

Please resolve the same with explanation.

Thanks
Nikhil[/img]
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PS Problem Of GMAT Prep
Nikhil

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by gauravgundal » Mon May 11, 2009 6:59 am
I will go for D

My approach is

there are total 6 number within 1 std dev. of the mean
= 10 -(0.3)*1= 9.7
and
= 10 +(0.3)*1 = 10.3

so
x/100 *8=6
Ans = 75%
Let me i know if i am correct
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by DeepakR » Mon May 11, 2009 8:57 am
Ya i too get the same: SD= 0.3 and Mean = 10.0

-------------------- +1 SD = 10.3

-------------------- Mean = 10.0

-------------------- -1 SD = 9.7

The following numbers are within this range from 9.7 to 10.3. They are:
9.9,9.9,9.9,10.0,10.0,10.2 = 6 numbers.

So 6/8 *100 = 75%=D.)

-Deepak

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by mail2nikhil01 » Mon May 11, 2009 10:17 pm
Thanks Deepak and gurav....I got the solution....If you have any theory or notes related to standard deviation...then could you please provide them

Thanks
Nikhil
Nikhil