An apparatus (typically electronic) incorporating an element (based on such processes as radioactive decay or random “noise”) and capable of generating a random sequence of outputs; used in tests of psi for generating target sequences, and in tests of psychokinesis may itself be the target system which the subject is required to influence, that is, by “biasing” the particular number or event output; a binary RNG has two equally-probable outputs; the term “RNG” is increasingly being used to refer to any system which produces naturally random outputs, such as bouncing dice, radioactive decay, or even, perhaps, the brain.