summaryAcomp: Summarizing a compositional dataset in terms of ratios

Description Usage Arguments Details Value Author(s) References See Also Examples

Description

Summaries in terms of compositions are quite different from classical ones. Instead of analysing each variable individually, we must analyse each pair-wise ratio in a log geometry.

Usage

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          ## S3 method for class 'acomp'
summary( object, ... ,robust=getOption("robust"))
          

Arguments

object

a data matrix of compositions, not necessarily closed

...

not used, only here for generics

robust

A robustness description. See robustnessInCompositions for details. The parameter can be null for avoiding any estimation.

Details

It is quite difficult to summarize a composition in a consistent and interpretable way. We tried to provide such a summary here, based on the idea of the variation matrix.

Value

The result is an object of type "summary.acomp"

mean

the mean.acomp composition

mean.ratio

a matrix containing the geometric mean of the pairwise ratios

variation

the variation matrix of the dataset ({variation.acomp})

expsd

a matrix containing the one-sigma factor for each ratio, computed as exp(sqrt(variation.acomp(W))). To obtain a two-sigma-factor, one has to take its squared value (power 1.96, actually).

invexpsd

the inverse of the preceding one, giving the reverse bound. Additionally, it can be "almost" intepreted as a correlation coefficient, with values near one indicating high proportionality between the components.

min

a matrix containing the minimum of each of the pairwise ratios

q1

a matrix containing the 1-Quartile of each of the pairwise ratios

median

a matrix containing the median of each of the pairwise ratios

q1

a matrix containing the 3-Quartile of each of the pairwise ratios

max

a matrix containing the maximum of each of the pairwise ratios

Author(s)

K.Gerald v.d. Boogaart http://www.stat.boogaart.de, R. Tolosana-Delgado

References

Aitchison, J. (1986) The Statistical Analysis of Compositional Data Monographs on Statistics and Applied Probability. Chapman & Hall Ltd., London (UK). 416p.

See Also

acomp

Examples

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compositions documentation built on Jan. 5, 2022, 5:09 p.m.