MjtTest {npordtests}

Modified Jonckheere-Terpstra (MJT) Test

Description

MjtTest performs MJT test.

Usage

MjtTest(formula, data, alpha = 0.05, na.rm = TRUE, verbose = TRUE)

Arguments

formula

a formula of the form lhs ~ rhs where lhs gives the sample values and rhs the corresponding groups.

data

a data frame containing the variables in the formula formula

alpha

the level of significance to assess the statistical difference. Default is set to alpha = 0.05.

na.rm

a logical value indicating whether NA values should be stripped before the computation proceeds.

verbose

a logical for printing output to R console.

Details

information.gain is

H(Class) + H(Attribute) - H(Class, Attribute)

.

gain.ratio is

\frac{H(Class) + H(Attribute) - H(Class, Attribute)}{H(Attribute)}

symmetrical.uncertainty is

2\frac{H(Class) + H(Attribute) - H(Class, Attribute)}{H(Attribute) + H(Class)}

Value

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

statistic

the MJT test statistic.

mean

the mean of the MJT test statistic.

variance

the variance of the MJT test statistic.

Z

the standardized test statistic.

p.value

the p-value of the test.

alpha

the level of significance.

method

the character string "MJT test ".

data

a data frame containing the variables in which NA values (if exist) are removed.

formula

a formula of the form lhs ~ rhs where lhs gives the sample values and rhs the corresponding groups.

Author(s)

Bulent Altunkaynak

References

Jonckheere, A. R. (1954). A Distribution-Free k-Sample Test Against Ordered Alternatives. Biometrika, 41, 133-145.

Neuhauser, M., Liu, P.Y., Hothorn, L.A.(1998). Nonparametric Tests for Trend: Jonckheere's Test, a Modification and a Maximum Test. Biometrical Journal, 40:8, 899-909.

Tryon, V. P., Hettmansperger, T. P. (1973). A class of nonparametric tests for homogeneity against ordered alternatives. Annals of Statistics, 1, 1061-1070.

Examples

library(npordtests)

## Data from Jonckheere (1954)
data(jdata)
MjtTest(Y~X,jdata)

## Data from Lehmann (1975)
data(lehmann)
MjtTest(Values~Group,lehmann)