MTest {PMCMRplus}R Documentation

Extended One-Sided Studentised Range Test

Description

Performs Nashimoto-Wright's extended one-sided studentised range test against an ordered alternative for normal data with equal variances.

This test is an extension of Hayter's OSRT (see osrtTest) by applying a simple order restriction of μ_{m'} - μ_m ≤ μ_j - μ_i ≤ \ μ_{l'} - μ_{l} for any l ≤ i ≤ m and m' ≤ j ≤ l'. It tests all-pairs \mathrm{H}_{ij}: μ_i ≥ μ_j against \mathrm{A}_{ij}: μ_i < μ_j$ for any $1 ≤ i < j ≤ k.

Usage

MTest(x, ...)

## Default S3 method:
MTest(x, g, alternative = c("greater", "less"), ...)

## S3 method for class 'formula'
MTest(
  formula,
  data,
  subset,
  na.action,
  alternative = c("greater", "less"),
  ...
)

Arguments

x

a numeric vector of data values, or a list of numeric data vectors.

...

further arguments to be passed to or from methods.

g

a vector or factor object giving the group for the corresponding elements of "x". Ignored with a warning if "x" is a list.

alternative

the alternative hypothesis. Defaults to greater.

formula

a formula of the form response ~ group where response gives the data values and group a vector or factor of the corresponding groups.

data

an optional matrix or data frame (or similar: see model.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.

na.action

a function which indicates what should happen when the data contain NAs. Defaults to getOption("na.action").

Value

Either a list with class "osrt" or a list with class "PMCMR".

method

a character string indicating what type of test was performed.

data.name

a character string giving the name(s) of the data.

statistic

the estimated statistic(s)

crit.value

critical R-values for α = 0.05.

alternative

a character string describing the alternative hypothesis.

parameter

the parameter(s) of the test distribution.

dist

a string that denotes the test distribution.

There are print and summary methods available.

A list with class "PMCMR" containing the following components:

method

a character string indicating what type of test was performed.

data.name

a character string giving the name(s) of the data.

statistic

lower-triangle matrix of the estimated quantiles of the pairwise test statistics.

p.value

lower-triangle matrix of the p-values for the pairwise tests.

alternative

a character string describing the alternative hypothesis.

p.adjust.method

a character string describing the method for p-value adjustment.

model

a data frame of the input data.

dist

a string that denotes the test distribution.

References

Nashimoto, K., Wright, F.T., (2005) Multiple comparison procedures for detecting differences in simply ordered means. Comput. Statist. Data Anal. 48, 291–306.

Examples

MTest(weight ~ group, data = PlantGrowth)

[Package PMCMRplus version 1.6.1 Index]