Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized for You

we will pick new questions that match your level based on your Timer History

Track Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

Current explanation implies one would calculate the stddev for the sequence.

Alternate explanation: They're all just skip+1 sets of the form f(n)=kn+x, k=2, no need to calculate stddev.

BELOW IS REVISED VERSION OF THIS QUESTION:

Which of the following sets has the standard deviation greater than the standard deviation of set X={-19, -17, -15, -13, -11}

I. A={1, 3, 5, 7, 9}

II. B={2, 4, 6, 8, 10}

III. C={1, -1, -3, -5, -7}

A. Set A only B. Set B only C. Set C only D. Sets A, B and C E. None of the sets

If we add or subtract a constant to each term in a set the standard deviation will not change.

Since each set can be obtained by adding some constant to each term of set X (20 for set A, 21 for set B and 12 for set C), then the standard deviations of all sets are the same.