Probability density may refer to:
- Probability density function in probability theory
- The product of the probability amplitude with its complex conjugate in quantum mechanics
According to quantum mechanics, these two are the same thing.
Famous quotes containing the word probability:
“Liberty is a blessing so inestimable, that, wherever there appears any probability of recovering it, a nation may willingly run many hazards, and ought not even to repine at the greatest effusion of blood or dissipation of treasure.”
—David Hume (1711–1776)