Probabilistic.

A probabilistic system is one that is governed by probability. Its behavior cannot be predicted exactly, but the probability of certain behaviors can be known.

Peter D. Elliott has written:

'Probabilistic number theory' -- subject(s): Probabilistic number theory

With a probabilistic method, each member of the population has the same probability of being selected for the sample. Equivalently, given a sample size, every sample of that size has the same probability of being the sample which is selected. With such a sample it is easier to find an unbiased estimate of common statistical measures. None of this is true for non-probabilistic sampling.

the probabilistic demarcation