metric_var {nexus}

Metric Variance and Standard Deviation

Description

• metric_var() computes the metric variance (or total variance), i.e. a global measure of spread.

• metric_sd() computes the metric standard deviation.

Usage

metric_var(x, ...)

metric_sd(x, ...)

## S4 method for signature 'CompositionMatrix'
metric_var(x)

## S4 method for signature 'CompositionMatrix'
metric_sd(x)

Arguments

x

A CompositionMatrix object.

...

Currently not used.

Details

The metric variance is the average of the CLR variances.

Value

A numeric vector.

Author(s)

N. Frerebeau

References

Boogaart, K. G. van den & Tolosana-Delgado, R. (2013). Analyzing Compositional Data with R. Berlin Heidelberg: Springer-Verlag. doi:10.1007/978-3-642-36809-7.

Hron, K. & Kubáček. L. (2011). Statistical Properties of the Total Variation Estimator for Compositional Data. Metrika, 74 (2): 221-230. doi:10.1007/s00184-010-0299-3.

Pawlowsky-Glahn, V. & Egozcue, J. J. (2001). Geometric Approach to Statistical Analysis on the Simplex. Stochastic Environmental Research and Risk Assessment, 15(5): 384-398. doi:10.1007/s004770100077.

See Also

Other statistics: aggregate(), covariance(), dist, mahalanobis(), margin(), mean(), quantile(), scale(), variation()

Examples

## Data from Aitchison 1986
data("hongite")

## Coerce to compositional data
coda <- as_composition(hongite)

## Mean
mean(coda)

## Quantile
quantile(coda)

## Metric variance
metric_var(coda)

## Metric standard deviation
metric_sd(coda)