What does sigma mean?

Answer 1

1.Sigma (upper case Σ, lower case σ, lowercase in word-final position ς) is the 18th letter of the Greek alphabet. In the system of Greek numerals it has a value of 200. When used at the end of a word, and the word is not upper case, the final form (ς) is used.

The letter is ultimately derived from Phoenician Sin . However, its name derives from Samekh.

In Eastern forms of Greek writing (as opposed to the Western Greek alphabet used in the European Greek colonies) and in the Middle Ages, the lunate sigma (upper case Ϲ, lower case ϲ) — which resembles, but which is not at all related to, the Latin letter C — was often used. Lunate sigma was frequently used for writing Medieval Greek, and it can still sometimes be seen in inscriptions in Greek Orthodox churches, but also in certain printed editions of classical authors. The form of the Cyrillic letter С [s] derives from lunate sigma.
Source(s):
http://en.wikipedia.org/wiki/sigma...

2.it's a Greek letter. You can assign it with any meanings. The capital sigma is most commonly associated with summation, series, infinite series. The small sigma is often used in statistics to denote standard deviation(Big sigma is often used to mean dhe covariance matrix too).. but these associations are weaker as u can use any letter or symbol to denote them. Small sigma is also used to mean the sigma field in probability theory.
sigma normally denotes true variance while data gives us sample variance, normally denoted by s^2. s is asymptotically sigma as number of data approaches infinity. but this is irrelevant for this question.

Answer 2

Sigma means the sum

Answer 3

Sigma is a Greek letter denoting usually summation in higher mathematics.

Answer 4

The word sigma means in mathematical sense the measure of the dispersion of a frequency distribution that is the square root of the arithmetic mean of the squares of the deviation of each of the class frequencies from the arithmetic mean of the frequency distribution; but it is also the 18th letter of the Greek Alphabet.

Answer 5

Sigma is a greek letter.

Answer 6

In addition to the answers you have already received, a lower case sigma is frequently used to denote stress, or force per unit of cross sectional area.

Answer 7

18th letter of the old Greek alphabet. Depends what context you are using it. See link for details.

Answer 8

it is a greek letter