Inclusive Graphic Standard Deviation

Description

Is the 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 95%, 84%, 16% and 5%

Related formulas

Variables

σiInclusive Graphic Standard Deviation (ϕ)
ϕ84Particle's percentage which corresponds to 84% phi unit (ϕ)
ϕ16Particle's percentage which corresponds to 16% phi unit (ϕ)
ϕ95Particle's percentage which corresponds to 95% phi unit (ϕ)
ϕ5Particle's percentage which corresponds to 5% phi unit (ϕ)