Explain Bayes' theorem.

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Bayes' theorem, named after 18th-century British mathematician Thomas Bayes, is a mathematical formula for determining conditional probability. Conditional probability is the likelihood of an outcome occurring, based on a previous outcome occurring. Bayes' theorem provides a way to revise existing predictions or theories (update probabilities) given new or additional evidence. Given the training data set D and data sample to be classified Xwhose class label is unknown. Let H be a hypothesis that X belongs to class C. Classification is to determine P(HX), the probability that the hypothesis holds given the observed data sample X.



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