Exchangeable events
From Wikipedia, the free encyclopedia
Let 
be a family of random events, and let 
be the indicator function for each of the events in ξ. Then ξ is said to be exchangeable if, for any permutation 
of the indexes 
, the two random vectors 
and 
have the same joint distribution.
With a more general view, a family of generic random variables is exchangeable if, for any permutation 
of the indexes , they have the same joint distribution.
Independent and identically random variables are exchangeable.
An interesting property of exchangeability is that the distribution function 
is symmetric in its arguments 
.
[edit] See also
[edit] References
Spizzichino, Fabio Subjective probability models for lifetimes. Monographs on Statistics and Applied Probability, 91. Chapman & Hall/CRC, Boca Raton, FL, 2001. xx+248 pp. ISBN 1-58488-060-0
