The conditional probability of a cause given its effect,
\[\begin{equation*}
P(A | B) = \frac{P(A) \, P(B | A)}{P(B)},
\end{equation*}
\]
| where | \(P(A \vert B)\) | is the posterior probability, |
| \(P(A)\) | is the likelihood, | |
| \(P(B \vert A)\) | is the prior probability, and | |
| \(P(B) \neq 0\) | is the evidence. |
N.B. If some probability, such as \(P(B)\) is unknown,