TAM (version 0.04-43)

tam.se: Standard Error Estimation

Description

Standard error computation for objects of the classes tam and tam.mml. Still to come for objects of class tam.jml.

Usage

tam.se(tamobj, ...)
tam.mml.se(tamobj, numdiff.parm = 0.001)

Arguments

tamobj

An object generated by tam.mml

numdiff.parm

Step width parameter for numerical differentiation

...

Further arguments to be passed

Value

• A list with following entries:
• xsi
  Data frame with $\xi$ parameters (est) an their corresponding standard errors (se)
• beta
  Data frame with $\beta$ regression parameters and their standard error estimates

Details

Covariances between parameters estimates are ignored in this standard error calculation. The standard error is obtained by numerical differentiation.

Examples

data(sim.rasch)
# estimate Rasch model
mod1 <- tam.mml(resp=sim.rasch) 
# standard error estimation
se1 <- tam.se( mod1 ) 

##   > print(se1$xsi, digits=3 )
##      xsi.index xsi.label     est     se
##   1          1        I1 -1.9590 0.0654
##   2          2        I2 -1.8570 0.0639
##   3          3        I3 -1.7444 0.0623
##   4          4        I4 -1.6407 0.0610