Sigma

Sigma is a concept that originates from the field of mathematics, but it has applications in various other disciplines such as statistics, physics, and engineering. It is represented by the Greek letter Σ (sigma), and it is used to denote the sum of a series of numbers.

Mathematics

In mathematics, sigma is used in summation notation to represent the sum of a series of numbers. The general form of a sigma notation is Σa_n, where a_n is the nth term of the series. The limits of the summation are usually specified above and below the sigma symbol.

Statistics

In statistics, sigma is used to represent the standard deviation, which is a measure of the amount of variation or dispersion in a set of values. A low standard deviation indicates that the values tend to be close to the mean of the set, while a high standard deviation indicates that the values are spread out over a wider range.

Physics

In physics, sigma is used to represent the Stefan–Boltzmann constant, which is a physical constant that describes the power radiated from a black body in terms of its temperature. It is also used to represent the cross section, which is a measure of the probability that a specific process will take place when some kind of particle or system of particles interacts with another particle or system of particles.

Engineering

In engineering, sigma is used to represent the stress on an object, which is the force per unit area applied to the object. It is also used to represent the surface charge density, which is the amount of charge per unit area on a surface.

See also

• Sigma (disambiguation)
• Summation
• Standard deviation
• Stefan–Boltzmann constant
• Stress (mechanics)

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