Hi swerve,

Standard Deviation is a relatively rare concept on the GMAT (you'll likely see it just once on Test Day). In addition, the GMAT will NEVER ask you to actually calculate S.D., so you really just need to understand the 'concept' behind that math. In simple terms, S.D. is about how 'spread out' a group of numbers is. The more 'spread out' the numbers, the higher the S.D.; the more 'close together' the numbers are, the lower the S.D. The smallest possible S.D. is 0 - and that's when all of the numbers in a group are the SAME.

Based on that last concept, the smallest S.D. among the 5 answer choices is...

Final Answer: A

GMAT assassins aren't born, they're made,
Rich

swerve wrote:Which of the following sets has the smallest standard deviation?

A. {2, 2, 2, 2, 2, 2}
B. {3, 4, 4, 4, 4, 5}
C. {1, 2, 3, 4, 5, 6}
D. {1, 1, 5, 8, 9, 11}
E. {1, 4, 4, 7, 9, 12}

The OA is A.

I need help to solve this PS question. Please, can any expert assist me with it? Thanks.

The smallest possible standard deviation for any set is 0, and the standard deviation of a set will be zero when all the data points are the same. Thus, the set from answer A will have a standard deviation of 0.

Answer: A