In [[statistics]], an '''exchangeable sequence of random variables''' (also sometimes '''interchangeable''')<ref name="ChowTeicher"/> is a sequence such that future observations behave like earlier observations,. meaningMore formally, thatthis anymeans orderthat (ofgiven a finite numbersequence of observations (i.e. of realizations of the random variables), any re-ordering of this sequence is equally likely to occur. This formalizes the notion of "the future being predictable on the basis of past experience." It is closely related to the use of [[independent and identically distributed random variables]] in statistical models. Exchangeable sequences of random variables arise in cases of [[simple random sampling]].
