denotes measure of dispersion probability distribution probability distribution scale parameter Philippe Rocca-Serra a probability distribution scale parameter is a measure of variation which is set by the operator when selecting a parametric probability distribution and which defines how spread the distribution is. The larger the value of the scale parameter is, the more spread out the distribution. adapted from Wikipedia: https://en.wikipedia.org/wiki/Scale_parameter. last accessed: 2016/11/11 scale statistical dispersion user request: https://github.com/ISA-tools/stato/issues/47 ready for release