Standard Deviation and Data Sufficiency

QOD2015_0220
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Standard Deviation and Data Sufficiency

QOD2015_0223
Explanation
Each set in I, II, and III can be transformed into a set identical to set Y by the addition of a positive or negative constant. In other words, though each set has a different mean, the elements in each set have the same distance from the set's mean. All the sets have the same standard deviation.

The correct choice is E.

Remember that when answering Data Sufficency questions, you can use process of elimination to rule out answer choices. If you can eliminate either A or B, then you can also eliminate choice D. If either Statement I alone or Statement II alone suffices to answer the question, then you can eliminate answer choices C and E.