 For a simplified example of the law, assume that a given event happens with a probability for its occurrence of 0.1%, within a single trial.Then, the probability that this so-called unlikely event does "not" happen (improbability) in a single trial is 99.9% (0.999).Already for a sample of 1000 independent trials, however, the probability that the event "does not" happen in any of them, even once (improbability), is only 0.9991000 ≈ 0.3677 = 36.77%.