# Definition of Bayes' theorem in English:

## Bayes' theorem

### noun

Statistics
• A theorem describing how the conditional probability of each of a set of possible causes for a given observed outcome can be computed from knowledge of the probability of each cause and the conditional probability of the outcome of each cause.

‘Following Bayes' theorem, the posterior distribution over the parameter space is proportional to the likelihood times the prior distribution.’
• ‘A follower of Clifford might object if there was no philosophical discussion of rival explanations or of the application here of Bayes' theorem in the theory of probability.’
• ‘Once these parameters have been estimated, Bayes' theorem is used to estimate the posterior probability that a given site came from the class of positively selected sites.’
• ‘To summarize the principle of our approach, we used Bayes' theorem to rewrite the posterior pdf as a function of a prior and a likelihood.’
• ‘The projections of the four individual submodels were integrated into a single prediction based upon Bayes' theorem.’

## Bayes' theorem

/ˈbāz ˌTHēərəm/ /ˈbeɪz ˌθiərəm/

### Origin

Mid 19th century named after Thomas Bayes (1702–61), English mathematician.