rcor.test {ltm}R Documentation

Pairwise Associations between Items using a Correlation Coefficient

Description

Computes and tests the pairwise associations between items using a correlation coefficient

Usage

rcor.test(mat, ...)

Arguments

mat a numeric matrix or a numeric data.frame containing the manifest variables as columns.
... extra arguments passed to cor() and cor.test().

Value

An object of class rcor.test with components,

cor.mat the correlation matrix.
p.values a three column numeric matrix containing the p-values for all the combinations of items.


The print method for class rcor.test returns a square matrix in which the upper diagonal part contains the estimates of the correlation coefficients, and the lower diagonal part contains the corresponding p-values.

Note

rcor.test() is more appropriate for informal testing of association between polytomous items.

Author(s)

Dimitris Rizopoulos dimitris.rizopoulos@med.kuleuven.be

Examples


## pairwise associations for Environment data:
rcor.test(data.matrix(Environment), method = "kendall")

## pairwise associations for independent normal random variates:
mat <- matrix(rnorm(1000), 100, 10, dimnames = list(NULL, LETTERS[1:10]))
rcor.test(mat)
rcor.test(mat, method = "kendall")
rcor.test(mat, method = "spearman")


[Package ltm version 0.8-1 Index]