From:

Henry George Liddell, Robert Scott, An Intermediate Greek-English Lexicon

stochazomai  ( stocazomai )

to aim or shoot at, endeavour after; to endeavour to make out, to guess at a thing, conjecture

stochastikos ( stocastikos )

skilful in aiming at, able to hit,  able to guess, sagacious

stochastês  

diviner,  one who aims at