se.boot {equate}R Documentation

Bootstrap Standard Errors of Equating

Description

This function returns the standard deviation of equated scores over multiple replications of a specified equating.

Usage

se.boot(x, y, xn = sum(x[,ncol(x)]), yn = sum(y[,ncol(y)]), 
  reps = 500, eqfun, ...)

Arguments

x, y score distributions of class “freqtab” for forms X and Y. Under the random groups design (i.e., no anchor test) x and y will each contain the score scale in column 1, and the number of examinees obtaining each score in column 2. For the nonequivalent groups design bivariate frequency tables are used, where columns 1 and 2 include all score combinations for the total and anchor test score scales, and column 3 contains the number of examinees obtaining each combination (see freqtab for details)
xn, yn integers specifying the number of scores to sample from each distribution at each replication (default is the total number of scores in each)
reps number of replications
eqfun string indicating the equating function
... further arguments passed to or from other methods

Details

Samples are drawn of size xn and yn, with replacement, from each score distribution. Form Y equivalents of each form X score are then obtained using the specified equating function eqfun. This process is repeated reps times.

This function is called by equate.

Value

Returns a vector of standard deviations, one per score scale point.

Author(s)

Anthony Albano tony.d.albano@gmail.com

Examples

xtab <- freqtab(KBneat$x[,1],0:36)
ytab <- freqtab(KBneat$y[,1],0:36)
se.boot(xtab,ytab,reps=100,eqfun="equate.ln")

[Package equate version 0.1-1 Index]