# What does symbol σ (Sigma) mean?

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### 3 thoughts on “What does symbol σ (Sigma) mean?”

1. Symbol σ is the letter of Greek, which expresses SIGMA in English (uppercase σ, lowercase σ, lowercase σ,), Chinese transliteration Sigma, is the eighteenth Greek letter. σ is a statistical unit used to measure a standard error in the total number, and it is also used to represent a chemical covalent bond and σ key.

This с с с and Latin alphabets are evolved from Sigma. Capital σ represents the sum of the sum of mathematics, which is commonly used in mathematics. It is mainly used to find multiple numbers, which is represented by ∑ (also known as harmonious number). The “σ” is expressed by the Eura (1707-1783) first used in 1755. This symbol is the head of Greek (increase), and “σ” is the capital of σ.
For the business or manufacturing process, the σ value can measure the ability to complete the non -defective operation of the process. The lower the σ value, the better the process is. The defect rate of general enterprises is about 3 to 4 Sigma. If the enterprise continues to pursue quality improvement and reaches the level of 6 Sigma, the performance will be almost perfectly achieved. 6 Sigma (6sigma) has evolved from a comprehensive quality management method in the mid -1990s to a highly effective corporate process design, improvement and optimization technology, and provided a series of new new applications for design, production and service. Product development tool.

2. “Sigma” is a Greek letter, and there are various ways to read as “Sima” and “Hima”. The symbol is ∑, English transliteration is Sigma, which means the sum of the sum of mathematics. For the sum of the sum of the number, it is represented by 数.如 The small characters below, such as i = 1, indicate the small characters above from i = 1, such as n represents the search until the nage nam is written below, the above is written n From X1 X2 … XN, if you write i = 5 below, write n above, and write xi (i lower corner) later indicates from X5 X6 … xn sigma (uppercase σ, lowercase σ). letter. In Greek, if the last letter of a single word is a lowercase Sigma, the letter should be written as a lower case of Sigma. In modern Greek numerals 6. Capital σ is used for: mathematical total symbolic lowercase σ is used for: a chemical covalent bond, σ key. Statistical standard deviations of the Silier letters and the L -Latin alphabet S all evolved from Sigma.

3. Sigma, indicating adding, for example: ∑xi = x1 x2 x3 …, generally restricts the range of i, for example, I is an integer from 1 to 10. In fact, the I here means the meaning of the first paragraph. For example, I want to calculate the sum of my 12 -month salary throughout the year. I can set the salary of the first month to XI. … X12