 The final piece of the basic language of probability theory corresponds to conditional probabilities. Where \(p\) and \(q\) are any propositions, the relevant expression is \(P\!\left(p\given q\right)\), which can be interpreted as “the probability of \(p\), given that all we know is \(q\).” For example,      \[     P\left(guilty\ggiven weapon\right)=0.7     \]   