Machine Learning & AI
Intermediate

Naive Bayes Posterior

Classifies by assuming features are conditionally independent given the class.

Formula

P(yx)P(y)iP(xiy)P(y\mid \mathbf{x}) \propto P(y)\prod_i P(x_i\mid y)

Variables

P(y)Class prior
P(x_i\mid y)Feature likelihood

Example

Multiply prior by each feature likelihood

Did You Know?

Its "naive" independence assumption is usually false, yet it works remarkably well for spam filtering.

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