Chapter
14
Poisson Distribution
SUMMARY POINTs
� Properties of a random variable X ~ Po ( � ) following Poisson distribution : 1 . The expected number of occurrences of an event is directly proportional to the length of the time interval 2 . The numbers of occurrences of the event in different disjoint time intervals are independent 3 . � : Mean number of occurrences of an event 4 . X : Number of occurrences of an event
� Formulae for Poisson distribution :
1 . |
r e
�� P ( X
�r) � for r � 0
, r � r!
|
2 . |
E ( X ) � �
: Expected value of X
|
3 . Var ( X )
� � : Variance of X 4 . � : Standard deviation of X 5 . P ( X � r) � P ( X � r �1 ) �1� P ( X � r � 1 )
Solutions of Chapter 14
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