An elementary proof of de Finetti's theorem.

A sequence of random variables is called exchangeable if the joint distribution of the sequence is unchanged by any permutation of the indices. De Finetti's theorem characterizes all { 0 , 1 } -valued exchangeable sequences as a 'mixture' of sequences of independent random variables. We present a new, elementary proof of de Finetti's Theorem. The purpose of this paper is to make this theorem accessible to a broader community through an essentially self-contained proof. [ABSTRACT FROM AUTHOR]