The older methods for the determination of the degree of a random mix was solely based on the calculation of a simple standard deviation. Physical characteristics like, density, average particle weight and size of each component was not considered. Therefore, the evaluation, when the state of a random mix is reached, was somewhat superficial. Poole, Taylor, and Wall  have derived equations, where the physical characteristics of the components were taken into consideration. By this means, it is possible to calculate, in advance, the theoretical coefficient of variation and the corresponding confidence limits. One can then experimentally follow under which conditions this state can be achieved.
VAİZOĞLU, Orhan (1999) "Assessment of the Degree of Mix of Powder Mixtures," Turkish Journal of Physics: Vol. 23: No. 1, Article 9. Available at: https://journals.tubitak.gov.tr/physics/vol23/iss1/9