zCompositions (version 1.5.0-4)

zVarArrayTest: Variation array homogeneity test

Description

This function performs a permutation test of the homogeneity of group-wise and overall variation arrays from all pair-wise log-ratios in a compositional data set. Groups can be defined by either zero/unobserved data patterns or by a grouping factor in fully observed zero-free data sets.

Usage

zVarArrayTest(X, label = 0, groups = NULL, b = 1000)

Value

Test p-values for log-ratio variances and means.

Arguments

X

Compositional data set (matrix or data.frame class).

label

Unique label (numeric or character) used to denote zeros/unobserved data in X (label = 0, default).

groups

Grouping factor in fully observed zero-free data sets (groups = NULL, default).

b

Number of bootstrap resamples used (b = 1000, default).

Details

The permutation test of homogeneity is based on total weighted squared relative errors (SRE) reflecting on divergence between group-wise variation arrays and overall (see zVarArrayError and zVarArray for more details). Note that for groups including less than two observations SRE is set to NA.

See Also

zPatterns, zVarArray, zVarArrayError.

Examples

data(Water)
zPatterns(Water, label = 0)
zVarArrayTest(Water)