Pairwise tests of independence for tables with one ordered nominal variable

Conducts pairwise tests for a 2-dimensional table, in which one variable is ordered nominal and one variable is non-ordered nominal. The function relies on the coin package.

Usage

pairwiseOrdinalIndependence(
  x,
  compare = "row",
  scores = NULL,
  method = "fdr",
  digits = 3,
  ...
)

Arguments

x: A two-way contingency table. One dimension is ordered and one is non-ordered nominal.
compare: If "row", treats the rows as the grouping variable. If "column", treats the columns as the grouping variable.
scores: Optional vector to specify the spacing of the ordered variable.
method: The method to adjust multiple p-values. See stats::p.adjust.
digits: The number of significant digits in the output.
...: Additional arguments, passed to stats::chisq_test.

Value

A data frame of comparisons, p-values, and adjusted p-values.

References

https://rcompanion.org/handbook/H_09.html

Author

Salvatore Mangiafico, mangiafico@njaes.rutgers.edu

Examples

### Independence test for table with one ordered variable
data(Breakfast)
require(coin)
chisq_test(Breakfast,
           scores = list("Breakfast" = c(-2, -1, 0, 1, 2)))
#> 
#> 	Asymptotic Generalized Pearson Chi-Squared Test
#> 
#> data:  Breakfast (ordered) by Travel (Walk, Bus, Drive)
#> chi-squared = 8.6739, df = 2, p-value = 0.01308
#> 
PT = pairwiseOrdinalIndependence(Breakfast, compare = "row")
PT
#>     Comparison p.value p.adjust
#> 1   Walk : Bus 0.12800   0.1570
#> 2 Walk : Drive 0.00462   0.0139
#> 3  Bus : Drive 0.15700   0.1570
cldList(comparison = PT$Comparison, 
        p.value    = PT$p.value, 
        threshold  = 0.05)
#>   Group Letter MonoLetter
#> 1  Walk      a         a 
#> 2   Bus     ab         ab
#> 3 Drive      b          b
        
### Similar to Kruskal-Wallis test for Likert data
data(PoohPiglet)
XT = xtabs(~ Speaker + Likert, data = PoohPiglet)
XT
#>         Likert
#> Speaker  1 2 3 4 5
#>   Piglet 1 6 2 1 0
#>   Pooh   0 0 1 6 3
#>   Tigger 0 0 2 6 2
require(coin)
chisq_test(XT,
           scores = list("Likert" = c(1, 2, 3, 4, 5)))
#> 
#> 	Asymptotic Generalized Pearson Chi-Squared Test
#> 
#> data:  Likert (ordered) by Speaker (Piglet, Pooh, Tigger)
#> chi-squared = 18.423, df = 2, p-value = 9.991e-05
#> 
PT=pairwiseOrdinalIndependence(XT, compare = "row")
PT
#>        Comparison  p.value p.adjust
#> 1   Piglet : Pooh 0.000310 0.000902
#> 2 Piglet : Tigger 0.000601 0.000902
#> 3   Pooh : Tigger 0.474000 0.474000
cldList(comparison = PT$Comparison, 
        p.value    = PT$p.value, 
        threshold  = 0.05)         
#>    Group Letter MonoLetter
#> 1 Piglet      a         a 
#> 2   Pooh      b          b
#> 3 Tigger      b          b