Graphic Standard Deviation


Is an approximate measure of sorting or variation of a particle size distribution in phi scale; can be estimated from the percentages of the particles which correspond to the percentages 84% and 16%

Related formulas


σgGraphic Standard Deviation (ϕ)
ϕ84Particle's percentage which corresponds to 84% phi unit (ϕ)
ϕ16Particle's percentage which corresponds to 16% phi unit (ϕ)