Bayesian classifiers

According to the Cambridge English Dictionary, bias is the action of supporting or opposing a particular person or thing in an unfair way, allowing personal opinions to influence your judgment. Bayesian machine learning refers to having a prior belief, and updating it later by using data. Mathematically, it is based on the Bayes formula:

One of the simplest Bayesian problems is randomly tossing a coin and trying to predict whether the output will be heads or tails. That is why we can identify Bayesian methodology as being probabilistic. Naive Bayes is very useful when you are using a small amount of data.