f(x) = B(alpha,beta)-1 xalpha-1(1-x)beta-1 on the interval (0,1).
Here B(alpha,beta) represents the beta function,
where G(x) is the gamma function. The Be(1,1) distribution is the uniform distribution, U(0,1).
The distribution of the kth order statistic of a sample of size n from the U(0,1) distribution is Be(k,n).