PMCMRplus (version 1.6.0)

MTest: 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 ${\mu }_{m^{\prime }}-{\mu }_m\le {\mu }_j-{\mu }_i\le {\mu }_{l^{\prime }}-{\mu }_l$ for any $l\le i\le m$ and $m^{\prime }\le j\le l^{\prime }$. It tests all-pairs ${\mathrm{H}}_{ij}:{\mu }_i\ge {\mu }_j$ against ${\mathrm{A}}_{ij}:{\mu }_i<{\mu }_j\$forany\$1\le i<j\le k$.

Usage

MTest(x, ...)
# S3 method for default
MTest(x, g, ...)
# S3 method for formula
MTest(formula, data, subset, na.action, ...)

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.

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

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

# NOT RUN {
MTest(weight ~ group, data = PlantGrowth)
# }