# Capital Sigma Symbol

The capital Greek letter Sigma (Σ), also known as the summation symbol, is used in algebra to represent the summation operator.

Format Display Data
TeX
\Sigma
Unicode Σ
931


## Usage

Summation | Operator

The capital letter Sigma Σ represents the summation operation in mathematics, often called sum for short. A sum has three parts: an initial value, an end value, and the expression being summed. The summation starts at the initial value and iterates, adding one to the value for each iteration, stopping when the value reaches the end value.

Expected Value Discrete Distribution | Formula

To calculate the expected value of a discrete distribution multiply all of the events of the distribution with the probability of the element occuring.

Population Mean | Formula

The population mean formula gives the average value of the whole population.

Series | Concept

A series is the operation of adding an infinite number expressions together. A series is denoted using the summation operator and the index variable k.

Standard Deviation | Formula

The sample standard deviation formula is denoted by the greek lower case sigma symbol in the case of the population and the latin letter s for the sample.