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, ...)

Arguments

X a data.frame containing binary variables.
n.print numeric indicating 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, etc.)

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

An object of class ltm with components,

perc a numeric matrix containing the percentages of positive and negative responses for each item.
items a numeric matrix containing the frequencies for the total scores.
pw.ass a matrix containing the p-values for the pairwise association between the items.
n.print the value of the n.print argument.
name the name of argument X.

Author(s)

Dimitris Rizopoulos dimitris.rizopoulos@med.kuleuven.be

Examples


## Descriptives for Wirs data:
descript(Wirs, 3)


[Package ltm version 0.3-0 Index]