DEFINITION of 'Empirical Probability'
A form of probability that is based on some event occurring, which is calculated using collected empirical evidence. An empirical probability is closely related to the relative frequency in a given probability distribution.
INVESTOPEDIA EXPLAINS 'Empirical Probability'
In order for a theory to be proved or disproved, empirical evidence must be collected. An empirical study will be performed using actual market data. For example, many empirical studies have been conducted on the capital asset pricing model (CAPM), and the results are slightly mixed.
In some analyses, the model does hold in real world situations, but most studies have disproved the model for projecting returns. Although the model is not completely valid, that is not to say there is no utility associated with using the CAPM. For instance, the CAPM is often used to estimate a company's weighted average cost of capital.

Probability Distribution
A statistical function that describes all the possible values ... 
Capital Asset Pricing Model  CAPM
A model that describes the relationship between risk and expected ... 
Modern Portfolio Theory  MPT
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Mutual Fund Theorem
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A Priori Probability
Probability calculated by logically examining existing information. ... 
Beta
A measure of the volatility, or systematic risk, of a security ...

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