An interpretation of quantum mechanics is an attempt to explain how the mathematical theory of quantum mechanics might correspond to experienced reality. Quantum mechanics has held up to rigorous and extremely precise tests in an extraordinarily broad range of experiments. However, there exist a number of contending schools of thought over their interpretation. These interpretations differ on such fundamental questions as whether quantum mechanics is deterministic or stochastic, local or nonlocal, which elements of quantum mechanics can be considered real, and what the nature of measurement is, among other matters.