Okuzeka
Statistics vocabulary · Probability

Bayes' theorem

Meaning in statistics, with examples

nounCommon term

In statistics, Bayes' theorem means: A rule for updating the probability of an event or hypothesis in the light of new evidence, linking P(A | B) to P(B | A): P(A | B) = P(B | A) × P(A) / P(B).

In Turkish: Bayes teoremi, Bayes kuralı

How it is used

Classic examples involve medical tests and spam filters. It is the basis of Bayesian statistics, in which a prior belief is combined with data to give a posterior distribution. Named after the 18th-century English minister Thomas Bayes.

Example sentences

  1. Bayes' theorem explains why most positive results from a screening test for a rare disease can be false positives.

  2. Apply Bayes' theorem to update the probability once you know the test result.

Common collocations

  • apply Bayes' theorem
  • Bayesian statistics
  • prior probability
  • posterior probability
  • conditional probabilityThe probability that an event happens given that another event has already happened, written P(A | B) and read 'the probability of A given B'.
  • probabilityA number between 0 and 1 that expresses how likely an event is: 0 means it cannot happen and 1 means it is certain.
  • independent eventsEvents where knowing that one has happened does not change the probability of the other; for two such events, P(A and B) = P(A) × P(B).

More terms: Probability

Practise with graded reading

Reading at the right level is the fastest way to make new words stick. Pick free English books by level: