descript {ltm}R Documentation

Descriptive Statistics for Response Matrices

Description

Computes the percentages of positive and negative responses for each item, as well the pairwise associations between items (see Details for more info).

Usage

descript(X, n.print = 10, ..., print = TRUE)

Arguments

X a data.frame containing binary variables.
n.print if print=TRUE gives the number of pairwise associations with the highest p-values to be printed.
... extra argument passed to chisq.test (e.g., simulate.p.value, B)
print logical; if TRUE the results are printed.

Details

Before an analysis with latent variable models, it is useful to inspect the data for evidence of positive correlations. In the case of binary data, this ad hoc check can be performed by constructing the 2 by 2 contingency tables for all possible pairs of items and examine the chi-squared p-values.

Value

If print=FALSE a list is returned with the following components,

perc a matrix containing the percentages of positive and negative responses for each item.
pw.ass a matrix containing the p-values for the pairwise association between the items.

Author(s)

Dimitris Rizopoulos dimitris.rizopoulos@med.kuleuven.be

Examples


## Descriptives for Wirs data:
descript(Wirs)
descript(Wirs, 3)
descript(Wirs, print=FALSE)


[Package ltm version 0.2-1 Index]