Sigma

Sigma as a letter in the Greek alphabet (Σ, σ, or ς) may refer to many things:

Related Topics:
Greek alphabet - Σ, σ, or ς

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• Upper-case letter Σ is used as a symbol for
• the summation operator forming a series in mathematics.
• a certain alphabet of a language, or of some other object dependent on an alphabet; expressed in mathematical terms, eg "the language defined by alphabet Σ={a,b,c} and the rules ..."
• The lower-case letter σ is used as a symbol for
• the standard deviation of a population in statistics.
• the divisor function in number theory.
• the Stefan-Boltzmann constant of radiation in physics.
• the Sigma factor of RNA polymerase in biology.

Sigma can also refer to:

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• a classification of quantum particle—see baryon.
• cell receptors in biochemistry and pharmacology.
• the name (Sigma) of the main villain from the video game series Mega Man X.
• a manufacturer (Sigma Corporation) of cameras, lenses and camera accessories.
• Sigma Designs, a company manufacturing ASICs for digital video appliances.
• a model of handgun manufactured by Smith and Wesson.
• a series of sailing yachts.
• the Mitsubishi Sigma, a variant of the Mitsubishi Galant.
• SIGMA (verification service), Nielsen Media Research's tracking system that allows Nielsen to electrionically monitor airplay of videos.
• the name of an insurance company active in Albania.
• Sigma, Capiz, a municipality in the Philippines.
• Sigma refers informally to the degree of exceptionality of a person or thing.
• Six Sigma is a quality management program; the name refers to six standard deviations.

As an acronym SIGMA can stand for the Society of Independent Gasoline Marketers of America.

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