Normal Distribution in a Nutshell - 170 GRE Mathematics

Normal Distribution applies to heights, weights, IQs, and much else, but how can you be tested on it? This video will cover the key phrase ‘normally distributed’ and why you should look out for it.

We must remember the 3 key percentages: 2%, 14% and 34% and how they are laid out on a bell curve.

From these, we can calculate that 68% of people lie within one standard deviation of the mean and 96% (or just a bit closer to 95%) lie within 2 standard deviations of the mean.

Do check out my other video on standard deviations if you want to learn more, but for this ‘normal distribution in a nutshell’ video, we can just leave it as a standardised measurement of spread.
Our two questions will be of medium and hard difficulty:

Q1. In a set of student exam results the 30th percentile corresponded to a score of 16 and the 40th percentile corresponded to a score of 27.

Quantity A
The 50th percentile score
Quantity B
38

Q2. The heights of a group of math teachers are normally distributed around the mean. If the median height is 175cm and the 84th percentile corresponds to a height of 181cm. Which of the following heights correspond to the 2nd percentile?
A) 161cm
B) 163cm
C) 165cm
D) 167cm
E) 168cm

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