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SD Ques

by Tarun Khanna » Wed Nov 02, 2011 10:17 pm
Hi

in the below ques, the OA is B....Can someone explain what is the basic underlying principle based on which the answer is B?

Is the range of a few numbers greater than $500?
(1) The median is $1,000 (2) Standard deviation is $500

thanks
tarun
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by shankar.ashwin » Wed Nov 02, 2011 10:32 pm
Range is (max)-(min) in a set. Median is the middle value.

(1) says median is 1000. This alone is not sufficient for the could have any other element in it. Insuff
(2) Given SD=500. Think of SD as the average deviation between two numbers.

Now if a set had 3 numbers and given their SD=500. 2 set of numbers will have SD<500 and the other 2 will have SD>500.
If SD>500 for any set 2 numbers, their range also is > 500 Sufficient. B

You could also use SD formulas. PIck any set of numbers and try.
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by gmatblood » Wed Nov 02, 2011 11:20 pm
Tarun Khanna wrote:Hi

in the below ques, the OA is B....Can someone explain what is the basic underlying principle based on which the answer is B?

Is the range of a few numbers greater than $500?
(1) The median is $1,000 (2) Standard deviation is $500

thanks
tarun
Please structure your question in a good way.

First present the Original question, then post the OA, only in SPOILER and then bring in your query.

Thanks
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by vaibhavgupta » Thu Nov 03, 2011 7:52 am
gmatblood wrote:
Tarun Khanna wrote:Hi

in the below ques, the OA is B....Can someone explain what is the basic underlying principle based on which the answer is B?

Is the range of a few numbers greater than $500?
(1) The median is $1,000 (2) Standard deviation is $500

thanks
tarun
Please structure your question in a good way.

First present the Original question, then post the OA, only in SPOILER and then bring in your query.

Thanks
I second gmatblood !
If OA is A, IMO B
If OA is B, IMO C
If OA is C, IMO D
If OA is D, IMO E
If OA is E, IMO A

FML!! :/
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