Beta Distribution
The Beta distribution is a very versatile function which can be used to model several different shapes of probability density curves, as shown below.
Beta (α1, α2) density functions [Law & Kelton (1991)]
The form of the Beta distribution is determined by the shape parameters α1 and α2. Both α1 and α2 are always > 0. The relationship between the Beta distribution shape parameters and the RocSlope2 input data is as follows:
The standard deviation is the positive square root of the variance.
The above equations apply to a beta random variable on [0,1]. To rescale and relocate to obtain a beta random variable on [α,b] of the same shape, use the transformation α + (b–α)Χ