PsiBeta (a1,a2,...)
PsiBeta (α1,α2) is a flexible distribution for modeling probabilities based on Bayesian statistics. The Beta distribution can be used as an approximation in the absence of specific distribution information. Typical uses include modeling time to complete a task in project networks and Bayesian Statistics.
The Beta distribution can take on a variety of shapes depending on the values of the two parameters α1 and α2. The Beta distribution with α1 = α2 = 1 is the Uniform (0,1) distribution. The Beta distribution with α1 = 1, α2 = 2 is the Left Triangular distribution. The beta distribution with α1 = 2, α2 = 1 is the Right Triangular distribution. A random variable X is defined by PsiBeta (α1,α2) if and only if 1 – X is defined by Beta (α2,α1).
