equate (version 1.1-3)

se.boot: 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 = 100, eqfun, returnboots = FALSE, ...)

Arguments

x, y

score distributions of class freqtab for forms X and Y. These may be univariate or bivariate distributions, as required by equate

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

returnboots

logical (default is FALSE) indicating whether or not the matrix of equated scores should be returned

...

further arguments passed to or from other methods

Value

• Returns either a vector of standard deviations, one per score scale point, or a matrix of equated scores with number of columns equal to reps

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 most easily called from equate.

Examples

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