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Manhattan Question Set # 19

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Manhattan Question Set # 19

by richachampion » Wed Oct 12, 2016 7:44 am
Set T consists of a certain number of even integers divisible by 3. Is standard deviation of T positive?

(1) All elements of set T are positive

(2) The range of set T is 0

OA: B
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Source: — Data Sufficiency |

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by [email protected] » Wed Oct 12, 2016 10:08 am
Hi richachampion,

This DS question is more of a 'conceptual' question than anything else. The Standard Deviation of a group of numbers will always be positive UNLESS every number in the group is the same (in which case the Standard Deviation will be 0).

We're told that all of the numbers in Set T are even integers that are multiples of 3. We're asked if the SD is POSITIVE. This is a YES/NO question.

1) All elements of set T are positive

IF.... Set T = {6, 12} then the answer to the question is YES.
IF... Set T = {6, 6} then the answer to the question is NO.
Fact 1 is INSUFFICIENT

2) The range of set T is 0

Since the range is 0, then all of the numbers in Set T must be the SAME number. Thus, the SD is 0 and the answer to the question is ALWAYS NO.
Fact 2 is SUFFICIENT

Final Answer: B

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by DavidG@VeritasPrep » Thu Oct 13, 2016 11:17 am
For a similar question, see here: https://www.beatthegmat.com/standard-dev ... 76816.html
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