68-95-99.7 rule

proper noun

The rule stating that a normal distribution will have 68% of its observations within one standard deviation of the mean, 95% within two, and 99.7% within three.

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Meanings

proper noun
  1. mnemonicmathematicsThe rule stating that a normal distribution will have 68% of its observations within one standard deviation of the mean, 95% within two, and 99.7% within three.

Translations

Russian пра́вило трёх си́гм
  • пра́вило трёх си́гм (právilo trjox sígm)statistics: empirical rule of 3σ
Cite this entry
APA

68-95-99.7 rule. (n.d.). In WatkinsX Dictionary. Retrieved November 5, 2026, from https://dictionary.watkinsx.com/word/68-95-99.7%20rule

MLA

“68-95-99.7 rule.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/68-95-99.7%20rule. Accessed November 5, 2026.

Chicago

WatkinsX Dictionary, s.v. “68-95-99.7 rule,” accessed November 5, 2026, https://dictionary.watkinsx.com/word/68-95-99.7%20rule.

Source: 68-95-99.7 rule on Wiktionary, CC BY-SA 4.0.