# Arithmetic mean size - 1st moment

## Description

Calculates the arithmetic mean size (arithmetic method of moments) of the particlesâ€™ size distribution of a soil, in metric scale. In statistics, the method of moments is a method of estimation of population parameters. One starts with deriving equations that relate the population moments to the parameters of interest. Then a sample is drawn and the population moments are estimated from the sample. The equations are then solved for the parameters of interest, using the sample moments in place of the (unknown) population moments. This results in estimates of those parameters.

Soil gradation is a classification of the particle size distribution of a soil.

## Variables

X_{a} | Arithmetic mean size - 1st moment (mm) |

f_{i} | Cumulative weight percent of the i particle size grade present (dimensionless) |

m_{mm} | Mid-point of the i particle size grade present (mm) |

## Categories

### External links