pairwiseSignTest: Pairwise sign tests for paired data

Description

Conducts pairwise sign tests across groups for paired data.

Usage

pairwiseSignTest(formula = NULL, data = NULL, x = NULL, g = 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.

method

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

...

Additional arguments passed to SIGN.test.

Value

A dataframe of the groups being compared, the p-values, and the adjusted p-values.

Details

The input should include either formula and data; or x, and g. The two sample paired sign test compares medians among two groups with paired data. See http://rcompanion.org/handbook/F_07.html for futher discussion of this test.

The pairwiseSignTest function can be used as a post-hoc method following an omnibus Friedman test. The function assumes that the data frame is already ordered by the blocking variable, so that the first observation of Group 1 is paired with the first observation of Group 2, and so on.

References

http://rcompanion.org/handbook/F_10.html

Examples

Run this code

data(BobBelcher)
BobBelcher = BobBelcher[order(BobBelcher$Instructor, BobBelcher$Rater),]
friedman.test(Likert ~ Instructor | Rater,
              data = BobBelcher)
BobBelcher$Instructor = factor( BobBelcher$Instructor, 
                  levels = c("Linda Belcher", "Louise Belcher",
                             "Tina Belcher", "Bob Belcher",
                             "Gene Belcher"))
PT = pairwiseSignTest(Likert ~ Instructor,
                      data   = BobBelcher,
                      method = "fdr")
PT
cldList(comparison = PT$Comparison,
        p.value    = PT$p.adjust,
        threshold  = 0.05)

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