The Maxwell-Boltzmann distribution
also called the Boltzmann distribution (Eisberg and Resnick 1985, pp. 381 and 384), gives the average number of indistinguishable particles of a system in equilibrium at temperature T found in a state of energy E. Here, k is Boltzmann's constant, T is the temperature, and specifies the number of particles in a particular system at temperature T.
Bose-Einstein Distribution, Fermi-Dirac Distribution
References
Eisberg, R. and Resnick, R. Quantum Physics of Atoms, Molecules, Solids, Nuclei, and Particles, 2nd ed. New York: Wiley, pp. 383-384, 1985.