variance

VAIR-ee-uhnss /ˈvɛəriəns/
nounC1GREGMATCAT
TechnicalScientificAcademic

The fact or quality of being different, divergent, or inconsistent; a statistical measure of dispersion.

In manufacturing, variance is the statistical spread of measurements around the average. High variance means poor quality control.

The story behind the word. The Latin root 'varius' referred to things that were speckled, bent, or changing. In modern science, it became the mathematical term for how much data 'speckles' away from the average.

Word relationships

  • variation: Variation is any change or difference, while variance is a specific statistical measure of how far numbers lie from the mean.
  • consistency: The quality of always behaving or performing in a similar way.

Commonly confused with

  • variety: Variety means a collection of different things; variance means an unwanted deviation from a standard.

Word family

  • vary (verb): To differ in size, amount, degree, or nature.
  • variable (adjective): Able to be changed or adapted.

Collocations

  • high variance
  • statistical variance
  • budget variance
  • reduce variance

Example sentences

  • "The quality control team noticed a high variance in the thickness of the steel plates, indicating poor manufacturing control." Steel mill quality audit

Memory hook

Think of a variety show where every act is completely different, representing high variance in entertainment. The spread of differences.

When not to use

Do not use as a direct synonym for 'variety' (which implies a pleasant diversity of choices).

Fun facts

  • The concept of variance is the foundation of modern portfolio theory in finance, where it is used to measure investment risk.

Related words

deviation, tolerance

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