Thursdays With Ron: Standard Deviation

by Manhattan Prep, Oct 15, 2010

Every other Thursday, our instructor Ron Purewal (known on the Beat the GMAT forums as lunarpower) hosts a free study hall session, called Thursdays with Ron, where anyone can submit questions ahead of time and attend. Ron chooses a few themes from the questions he gets and goes over strategies for them.

In this session, Ron explains what you need to know about Standard Deviation for the GMAT:

Heres an outline of what Ron covers, with the minute markers. Make sure to watch the video, though, so that youre able to follow along!

• 00:00 Standard deviation is a measure of spread, so the farther the data are from the mean, the farther the standard deviation
• 00:33 What you DON'T have to know about standard deviation
• 1:40 What you need to know is how to make the standard deviation bigger or smaller
• 2:00 How to make the standard deviation bigger or smaller.
• 3:30 How would you add additional data points to increase standard deviation?
• 4:28 The one thing you can do to guarantee you will increase the standard deviation is to add in data points that are outside the current range.
• 6:14 How would you add additional points that would decrease the standard deviation?

If you want to view recordings of past Thursdays with Ron or submit questions for the next live session, which takes place on October 21, you can do so here.