Tree diagram (probability theory)

A tree diagram may represent a series of independent events (such as a set of coin flips) or conditional probabilities (such as drawing cards from a deck, without replacing the cards).

The root node represents the certain event and therefore has probability 1.

Each set of sibling nodes represents an exclusive and exhaustive partition of the parent event.

The probability associated with a node is the chance of that event occurring after the parent event occurs.

The probability that the series of events leading to a particular node will occur is equal to the product of that node and its parents' probabilities.