Sigma

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

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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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Greek alphabet: The Greek language is written in the Greek alphabet, developed in classical times (ca 9th century B.C.) and passed down to the present. It is the world's oldest alphabet in use today. In ancient Greece its letters were also used to represent numbers, called Greek numerals, analogous to Roman numeral...

Sigma related Images and Photos (experimental)

Delta Sigma Theta Always a Lady