fp.test: Fligner-Policello test

Description

Performs a Fligner-Policello test of the null that the medians in the two groups (samples) are the same.

Usage

fp.test(x, ...)
# S3 method for default
fp.test(x, y, delta = 0, alternative = "two.sided", ...)
# S3 method for formula
fp.test(formula, data, subset, ...)

Value

statistic: test statistics.
p.value: p-value of the test.
alternative: a character string describing the alternative hypothesis.
method: a character string indicating the name of the test.
data.name: a character string giving the names of the data.
null.value: the specified hypothesized value of the median difference.

Arguments

x: a numeric vector of data values.
y: a numeric vector of data values.
delta: null difference in medians tested.
alternative: a character string specifying the alternative hypothesis, must be one of "two.sided" (default), "greater" or "less".
formula: a formula of the form a ~ b, where a and b give the data values and corresponding groups.
data: an optional data frame containing the variables in the formula formula. By default the variables are taken from environment(formula).
subset: an optional vector specifying a subset of observations to be used.
...: further arguments to be passed to or from other methods.

Author

Maxime HERVE <maxime.herve@univ-rennes1.fr>

Details

The Fligner-Policello test does not assume that the shape of the distribution is similar in two groups, contrary to the Mann-Whitney-Wilcoxon test. However, it assumes that the the distributions are symmetric.

Examples

Run this code

x <- rpois(20,3)
y <- rpois(20,5)
fp.test(x,y)

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