kurtosis

English

Etymology

Coined by English mathematician, biometrician, and eugenicist Karl Pearson c. 1895 (published 1899 in "On certain Properties of the Hypergeometrical Series, and so on the fitting of such series to Observation Polygons in the Theory of Chance", Phil. Mag.). From Ancient Greek κύρτωσις (kúrtōsis, “a bulging, convexity”), from κυρτός (kurtós, “bulging, convex”).

Pronunciation

• enPR: kər-tō′sĭs
  • (Received Pronunciation) IPA^(key): /kəˈtəʊ.sɪs/, /ˌkɜːˈtəʊ.sɪs/
  • (General American, Canada) IPA^(key): /kɚˈtoʊ.sɪs/, /ˌkɝˈtoʊ.sɪs/
  • (General Australian) IPA^(key): /kəˈtəʉ.sɪs/, /kəˈtɐʉ.sɪs/, /ˌkɜːˈtəʉ.sɪs/, /ˌkɜːˈtɐʉ.sɪs/

Noun

kurtosis (countable and uncountable, plural kurtoses or kurtosises)

1. (statistics) A measure of "heaviness of the tails" of a probability distribution, defined as the fourth cumulant divided by the square of the variance of the probability distribution.
2. (statistics) Excess kurtosis: the difference between a given distribution's kurtosis and the kurtosis of a normal distribution.

Derived terms

• excess kurtosis
• heterokurtosis
• homokurtosis
• leptokurtic
• leptokurtosis
• mesokurtic
• mesokurtosis
• platykurtic
• platykurtosis

Translations

measure of "tail heaviness"

• Catalan: curtosi f
• Chinese:

  Mandarin: 峰度 (fēngdù)

• Czech: špičatost f, koeficient špičatosti m
• Finnish: huipukkuus (fi), kurtoosi (fi)
• French: kurtosis (fr) m, coefficient d’aplatissement m
• German: Kurtosis f, Wölbung (de) f
• Portuguese: curtose f
• Russian: эксце́сс (ru) m (ekscéss), коэффицие́нт эксце́сса m (koefficiént ekscéssa)
• Spanish: curtosis f
• Tagalog: umbok (tl)

Further reading

• “kurtosis”, in OneLook Dictionary Search.
• “kurtosis”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.
• “kurtosis”, in The American Heritage Dictionary of the English Language, 5th edition, Boston, Mass.: Houghton Mifflin Harcourt, 2016, →ISBN.
• “kurtosis, n.”, in Lexico, Dictionary.com; Oxford University Press, 2019–2022.