covariance

== English == === Etymology === From co- + variance. === Pronunciation === (UK) IPA(key): /kəʊˈvɛː.ɹi.əns/ (US, without the Mary–marry–merry merger) IPA(key): /koʊˈvæɹ.i.əns/ (US, Mary–marry–merry merger) IPA(key): /ˈkoʊˈvɛɹ.i.əns/ (Australian) IPA(key): /kəʉˈveː.ɹi.əns/ === Noun === covariance (countable and uncountable, plural covariances) (statistics) A statistical measure defined as Cov ⁡ ( X , Y ) = E ⁡ ( ( X − μ ) ( Y − ν ) ) {\displaystyle \scriptstyle \operatorname {Cov} (X,Y)=\operatorname {E} ((X-\mu )(Y-\nu ))} given two real-valued random variables X and Y, with expected values E ( X ) = μ {\displaystyle \scriptstyle E(X)\,=\,\mu } and E ( Y ) = ν {\displaystyle \scriptstyle E(Y)\,=\,\nu } . (object-oriented programming) The conversion of data types from wider to narrower in certain situations. Coordinate term: contravariance ==== Derived terms ==== ==== Related terms ==== covariant ==== Translations ==== === Further reading === covariance on Wikipedia.Wikipedia covariance and contravariance (computer science) on Wikipedia.Wikipedia Covariance on Wolfram MathWorld == French == === Pronunciation === IPA(key): /kɔ.va.ʁjɑ̃s/ === Noun === covariance f (plural covariances) (statistics) covariance (object-oriented programming) covariance === Further reading === “covariance”, in Trésor de la langue française informatisé [Digitized Treasury of the French Language], 2012