Difference between revisions of "Probability mass function"

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In [[probability theory]], a ''probability mass function'' say ''p'' is a real valued function of a discrete variable say ''x'', such that the value ''p(x<sub>k</sub>)'' is the probability of the variable ''x'' having the value x<sub>k</sub>.   
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In [[probability theory]], a '''probability mass function''' say ''p'' is a real valued function of a discrete variable say ''x'', such that the value ''p(x<sub>k</sub>)'' is the probability of the variable ''x'' having the value x<sub>k</sub>.   
  
 
In order to qualify, such a function must meet the following criteria:
 
In order to qualify, such a function must meet the following criteria:

Revision as of 21:18, February 8, 2008

In probability theory, a probability mass function say p is a real valued function of a discrete variable say x, such that the value p(xk) is the probability of the variable x having the value xk.

In order to qualify, such a function must meet the following criteria:

<math>p(x_{k}) \geq 0 </math> <math> \forall x </math>


<math>\sum_{k} p(x_{k}) = 1 </math>


The collection of pairs ( xk , p(xk) ) is the (discrete) probability distribution of x.