Standard Deviation in a Nutshell – 170 GRE Quant

Standard Deviation simply calculates how spread out, on average, numbers are away from the mean.
Don’t worry too much about the fancy formula. The GRE virtually never tests it, in my experience. I have done one example at the end of video anyway, just in case, to show how to calculate standard deviation.


I offer private GRE / GMAT tutoring online at a fixed rate of $140/hr. Please get in touch via the email below, or through my tutoring website: https://www.gretutorlondon.com/

Enquiries: [email protected]

First secret: Standard Deviation has nothing to do with the median!

Next secret: The Range is only Relevant if the range is zero. Otherwise you cannot use the range to calculate the standard deviation of a set of numbers.

So how is standard deviation actually tested on the GRE then?

Here is a classic question:

Six hundred applicants for several post office jobs were rated on a scale from 1 to 50 points. The ratings had a mean of 32.5 points and a standard deviation of 7.1 points. How many standard deviations above or below the mean is a rating of 48 points?

What does ‘Within 2 standard deviations’ mean? It means within 2 standard deviations above OR below the mean. We will show this, using a bell curve.

Finally, we will calculate an actual standard deviation quantity on a small set of numbers:
4, 5, 7, 11, 13

This will not only be helpful for calculating standard deviation on the GRE, but also for gaining some statistics GRE practice. These standard deviation questions should help illustrate ways to get a GRE 170 Quant score.


I offer private GRE / GMAT tutoring online at a fixed rate of $140/hr. Please get in touch via the email below, or through my tutoring website: https://www.gretutorlondon.com/

Enquiries: [email protected] If you’re now ready to get into your dream MBA program, my former student, Angel, is offering virtual private Admissions coaching. She was admitted into Harvard Business School, The Wharton School of Business, and Columbia Business School (accepted into every school she interviewed for) after graduating from UCLA with a degree in Communication. She also got 3 perfect scores on the GRE’s Analytical Writing Assessment (99th percentile).

Here is her link - https://linktr.ee/angel_accel - and you can reach her at [email protected] with the subject line, “PHILIP SENT ME.”