law of averages

American  

noun

1. a statistical principle formulated by Jakob Bernoulli to show a more or less predictable ratio between the number of random trials of an event and its occurrences.

2. Informal. the principle that, in the long run, probability as naively conceived will operate and influence any one occurrence.

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law of averages British  

noun

1. (popularly) the expectation that a possible event is bound to occur regularly with a frequency approximating to its probability, as in the (actually false) example Compare law of large numbers

   after five heads in a row the law of averages makes tails the better bet

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law of averages Idioms  

1. The idea that probability will influence all occurrences in the long term, that one will neither win nor lose all of the time. For example, If it rains every day this week, by the law of averages we're bound to get a sunny day soon. This colloquial term is a popular interpretation of a statistical principle, Bernoulli's theorem, formulated in the late 1600s.

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Example Sentences

See Examples For:

law of averages

The problem, of course, is that the law of averages works well for large populations, but no one lives an “average” life.

From MarketWatch ● Jul. 11, 2026

I went with the law of averages when I picked a Newcastle home victory last week, so hopefully the same method will work again with Chelsea this time.

From BBC ● Mar. 7, 2024

“It’s been a little bit tougher for me this year. Hopefully the law of averages says it’s going to get a little better.”

From Washington Times ● Jun. 1, 2023

Or perhaps the law of averages dictated that a few breaks had to start going their way.

From Seattle Times ● Nov. 22, 2021

Would the law of averages catch up to him?

From "The Chocolate War" by Robert Cormier