Conditional probabilities are just that: probabilities of an occurrence conditional upon something else happening. Technically speaking, the joint probability of the two items occurring is divided by the marginal probability of the conditioning event. In this case, the table indicates the joint probability of an 18% return, given the economic outlook is normal at 15%. The marginal probability that the economic outlook is normal sums to 50%, so the conditional probability is 15% / 50% or 30%.

(Book 2, Module 15.1, LO 15.b)