This document discusses classical and quantum statistics. It explains that classical statistics, developed by Maxwell, Boltzmann, and Gibbs, were able to explain many macroscopic phenomena but failed to explain others observed at low temperatures. This led to the development of quantum statistics by Bose, Einstein, Fermi and Dirac. Bose-Einstein statistics applies to indistinguishable particles with integer spin like photons that can occupy the same state. Fermi-Dirac statistics applies to particles with half-integer spin like electrons that cannot occupy the same state due to the Pauli exclusion principle. Quantum statistics accounts for the discrete, probabilistic nature of energy at the quantum scale.