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Industrial Engineering & Manufacturing vocabulary · Six Sigma and Statistics

Standard deviation

Meaning in industrial engineering & manufacturing, with examples

nounCommon term

In industrial engineering & manufacturing, standard deviation means: A number that shows how widely values are spread around their average; a small standard deviation means the results are close together. Its symbol is σ (sigma).

In Turkish: standart sapma

How it is used

Used everywhere in quality and Six Sigma work, from control limits to capability indices. People calculate the standard deviation of a sample and say values are 'within two sigma' or 'three standard deviations from the mean'.

Example sentences

  1. The mean fill weight is 500.4 g with a standard deviation of 0.8 g.

  2. Control limits are set at three standard deviations above and below the mean.

Common collocations

  • calculate the standard deviation
  • sample standard deviation
  • three standard deviations
  • high standard deviation
  • variationThe natural differences between the results of the same process, for example small changes in the diameter of parts made on the same machine.
  • process capabilityHow well a stable process can produce parts within the specification limits, usually expressed with indices such as Cp and Cpk.
  • control chartA graph that shows measurements of a process over time, with a center line and upper and lower control limits, so you can see whether the process is stable.
  • Six SigmaA data-driven method for improving processes by reducing variation and defects, aiming for no more than 3.4 defects per million opportunities.

This word in other fields

The same English word can have a different meaning in another field:

More terms: Six Sigma and Statistics

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