Archived | Population Genetics and Statistics for Forensic Analysts | Logical Approach

Bayes Theorem

Many statisticians have employed what is known as Bayesian probability, after the British clergyman Thomas Bayes, which is based on probability as a measure of one's degree of belief.⁰¹ This type of probability is conditional in that the outcome is based on knowing information about other circumstances and is derived from Bayes Theorem, published in 1764.¹⁴

Conditional Probability

Conditional probability, by definition, is the probability P of an event A given that an event B has occurred.¹⁵ Mathematically, conditional probabilities can be represented as: P(A | B) where "|" means "given that."

**Example:**
Take the example of a die with six sides. If one was to throw the die, the probability of it landing on any one side would be 1/6. This probability, however, assumes that the die is not weighted or rigged in any way, and that all of the sides contain a different number. If this were not true, then the probability would be conditional and dependent on these other factors.

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Date Created: July 17, 2023

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