### Definition(s)

#### Conditional Probability

Statistical distribution (probability) of the occurrence of a variable A, given that other variables B, C, … have certain assigned values

NOTE The conditional probability of A given that B, C, … occur is written as P(AIB,C, … ). The concept is applicable to

metocean parameters, as well as to actions and action effects.

EXAMPLE When considering wave parameters, A can be the individual crest elevation, B the water depth and C the

significant wave height, and so on.

Source: API RP 2MET, Derivation of Metocean Design and Operating Conditions, First Edition, November 2014. Global Standards

#### Conditional Probability

Conditional probability is the probability of some event A, given the occurrence of some other event B, written as P(A|B). An example is the conditional probability of a person dying (event A), given that they contract the pandemic flu (event B).

Sample Usage: An individual has a higher conditional probability of developing a fever if they contract influenza.

Source: DHS Risk Lexicon, U.S. Department of Homeland Security, 2010 Edition. September 2010 Regulatory Guidance