# 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

σ_{i} | Inclusive Graphic Standard Deviation (ϕ) |

ϕ84 | Particle's percentage which corresponds to 84% phi unit (ϕ) |

ϕ16 | Particle's percentage which corresponds to 16% phi unit (ϕ) |

ϕ95 | Particle's percentage which corresponds to 95% phi unit (ϕ) |

ϕ5 | Particle's percentage which corresponds to 5% phi unit (ϕ) |

## Categories

### External links