We have seen that Bayes' rule computes P(A|B) in terms of P(B|A). The expression P(B|A) is called the likelihood of A. In the example above A had two values a1 and a2. The ratio

is called the likelihood ratio. In the example the likelihood ratio computes to 405/15 = 27. This tells us that the 'odds' on the bag being the one mainly with white balls is 27 to 1.