What defines a normal distribution?

Nov 2, 2015

A bell shaped Frequency Distribution defines Normal Distribution.
It is a continuous Frequency Distribution.

Explanation:

A distribution to be called as normal distribution, it must possess the following features -

The curve must be symmetric. It should not have skewness.

It must be neither too flat (platykurtic) nor too peaked (leptokurtic). It is mesokurtic.

Its arithmetic mean must equal its median and mode.

Relationship among its mean, standard deviation, frequencies and area is unique.

68.26% of the total frequency lies between $x + \sigma$ and $x - \sigma$
95.44% of the total frequency lies between $x + 2 \sigma$ and $x - 2 \sigma$
99.74% of the total frequency lies between $x + 3 \sigma$ and $x - 3 \sigma$