The occurrence of events can be distinguished along a spectrum of stochasticity (randomness), on the one hand, and determinism on the other. Something that is purely deterministic simply happens, in a proscribed manner and in response to a specific set of conditions, all with absolute likelihood.
Something that is purely stochastic, by contrast, simply does not occur in one specific way with certainty but instead will vary between two or more possible outcomes. We can think of stochasticity as or the random picking of a card, something that introduces to a process, whereas the more precise a process then the greater its determinism.
Note that in reality almost all things are deterministic but in many cases simply sufficiently complex that it is not possible to predict what is going to happen with high . That , for example, may not be sufficiently known or understood. Alternatively, some systems are sufficiently canalized that a specific outcome is highly likely despite variation in initial conditions.
Ha ha, this kind of blows your mind: