The word for today is…
stochastic (adj) – 1. Of, relating to, or characterised by conjecture; conjectural.
2. Statistics Involving or containing a random variable or process.
Source : The Free Dictionary
Etymology : 1660s, “pertaining to conjecture,” from Greek stokhastikos “able to guess, conjecturing,” from stokhazesthai “to guess, aim at, conjecture,” from stokhos “a guess, aim, target, mark,” literally “pointed stick set up for archers to shoot at,” from PIE *stogh-, variant of root *stegh- “to stick, prick; pointed”. The sense of “randomly determined” is from 1934, from German stochastik (1917).