Normal

Overview


The normal distribution is the standard probability distribution known as the Guassian, or the bell curve. It is one or the most common distributions used in statistical modeling, usually because of its use in the central limit theorem.
The normal distribution exhibits a characteristic bell shape.

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Formal Definition


The normal density function is given by
{% f(x) = \sqrt{1/2\pi \sigma^2 } \times e ^{-0.5 [(x-\mu)/\sigma]^2} %}
For multivariable distributions
{% f(\vec{x}| \vec{\mu}, \Sigma) = \frac{1}{(2\pi )^{D/2} | \Sigma | ^{1/2}} exp[-\frac{1}{2} (\vec{x} - \vec{\mu})^T \Sigma ^{-1} (\vec{x} - \vec{\mu}) ] %}
(see Murphy chpt 4)

Properties


Library


A library for calculating normal distributions can be found at normal library

Contents