eRm (version 1.0-9)

print.eRm: Methods for extended Rasch models

Description

Several methods for objects of class 'eRm'.

Usage

# S3 method for eRm
print(x, ...)
# S3 method for eRm
summary(object, ...)
# S3 method for eRm
coef(object, parm="beta", ...)
# S3 method for eRm
model.matrix(object, ...)
# S3 method for eRm
vcov(object, ...)
# S3 method for eRm
logLik(object, ...)
# S3 method for eRm
confint(object, parm = "beta", level = 0.95, ...)

Value

The methods below are extractor functions and return various quantities:

vcov returns the variance-covariance matrix of the parameter estimates,

coef a vector of estimates of the eta or beta basic parameters,

model.matrix the design matrix,

logLik an object with elements loglik and df containing the log-likelihood value and df.

confint a matrix of confidence interval values for eta or beta.

Arguments

x

Object of class eRm.

object

Object of class eRm.

parm

Either "eta" or "beta".

level

Alpha-level.

...

Further arguments to be passed to or from other methods. They are ignored in this function.

Author

Patrick Mair, Reinhold Hatzinger

Details

The print method displays the value of the log-likelihood, parameter estimates (basic parameters eta) and their standard errors. For RM, RSM, and PCM models, the etas are difficulty parameters, for the LLTM, LRSM, LPCM the sign of the parameters depend on the design matrix and are easiness effects by default. The summary method additionally gives the full set of item parameters beta as easiness parameters for all models.

Print methods are also available for the functions logLik and confint (see below).

Examples

res <- RM(raschdat1)
res
summary(res)
coef(res)
vcov(res)
model.matrix(res)
logLik(res)