In information theory, the **conditional entropy** (or **equivocation**) quantifies the amount of information needed to describe the outcome of a random variable given that the value of another random variable is known. Here, information is measured in bits, nats, or bans. The *entropy of conditioned on * is written as .

Read more about Conditional Entropy: Definition, Chain Rule, Generalization To Quantum Theory, Other Properties

### Famous quotes containing the words conditional and/or entropy:

“The population of the world is a *conditional* population; these are not the best, but the best that could live in the existing state of soils, gases, animals, and morals: the best that could yet live; there shall be a better, please God.”

—Ralph Waldo Emerson (1803–1882)

“Just as the constant increase of *entropy* is the basic law of the universe, so it is the basic law of life to be ever more highly structured and to struggle against *entropy*.”

—Václav Havel (b. 1936)