Probabilistic, the exact behaviour of a stochastic system or process is not known precisely ahead of time, but relative probabilities of outcomes is known.

Loaded (or unloaded, for that matter) dice count as stochastic: I know my d6 gives me a 5 about seven times out of ten, the other five values sharing rather evenly the remaining 30%. I don't know what a particular role will be, but am fairly sure that it will be 5 much more often than anything else.