pairwisePermutationSymmetryMatrix: Pairwise two-sample permutation symmetry tests with matrix output

Description

Conducts pairwise two-sample permutation tests for symmetry across groups.

Usage

pairwisePermutationSymmetryMatrix(formula = NULL, data = NULL,
  x = NULL, g = NULL, b = NULL, method = "fdr", ...)

Arguments

formula

A formula indicating the measurement variable and the grouping variable. e.g. y ~ group.

data

The data frame to use.

The response variable as a vector.

The grouping variable as a vector.

The blocking variable as a vector.

method

The p-value adjustment method to use for multiple tests. See stats::p.adjust.

...

Additional arguments passed to coin::symmetry_test.

Value

A list consisting of: A matrix of p-values; the p-value adjustment method; a matrix of adjusted p-values.

Details

The input should include either formula and data; or x, g, and b.

Permutation tests are non-parametric tests that do not assume normally-distributed errors. See http://rcompanion.org/rcompanion/d_06a.html for futher discussion of this test.

The pairwisePermutationSymmetryMatrix function can be used as a post-hoc method following an omnibus permutation test analogous to a paired one-way analysis of variance. The matrix output can be converted to a compact letter display.

References

http://rcompanion.org/handbook/K_03.html

Examples

Run this code

# NOT RUN {
data(BobBelcher)
BobBelcher$Instructor = factor( BobBelcher$Instructor, 
                  levels = c("Linda Belcher", "Louise Belcher",
                             "Tina Belcher", "Bob Belcher",
                             "Gene Belcher"))
BobBelcher$Likert.f = factor(BobBelcher$Likert, ordered=TRUE)
PT = pairwisePermutationSymmetryMatrix(Likert.f ~ Instructor | Rater,
                                       data   = BobBelcher,
                                       method = "fdr")$Adjusted
PT
library(multcompView)
multcompLetters(PT,
                compare="<",
                threshold=0.05,
                Letters=letters)   

# }

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