PREp: Percent Relative Error

In kequate: The Kernel Method of Test Equating

Percent Relative Error

Description

Calculates the percent relative error (PRE) between an equated distribution and the reference distribution for the first ten moments.

Usage

PREp(eq, obs, r, s)

Arguments

eq	A numeric vector containing the equated values from X to Y or Y to X.
obs	The score vector of test Y or X.
r	A vector of probabilities corresponding to the equated values.
s	A vector of probabilities corresponding to the score values of test Y or X.

Details

If we equate test X to test Y, then we have equated values eYx with estimated probabilities r and estimated probabilities s for the score values on Y. To compare the moments between these two distributions, we can calculate the percent relative error (PRE) between them. If we denote the p:th moment of Y and eYx by μ(Y) and μ(eYx) respectively, the PRE for moment p is defined as

PRE(p) = 100*(μ(eYx)-μ(Y))/μ(Y).

Value

A numeric vector containing the percentage relative error for the first ten moments.

Author(s)

[e-mail]
[e-mail]
[e-mail]

References

Andersson, B., Branberg, K., Wiberg, M. (2013). Performing the Kernel Method of Test Equating with the Package kequate. Journal of Statistical Software, 55(6), 1–25. <doi: 10.18637/jss.v055.i06>

von Davier, A.A., Holland, P.W., Thayer, D.T. (2004). The Kernel Method of Test Equating. Springer-Verlag New York.

See Also

glm kequate

Examples

P<-c(5, 20, 35, 25, 15)
Q<-c(10, 30, 30, 20, 10)
x<-0:4
glmx<-glm(P~I(x)+I(x^2), family="poisson", x=TRUE)
glmy<-glm(Q~I(x)+I(x^2), family="poisson", x=TRUE)
keEG<-kequate("EG", 0:4, 0:4, glmx, glmy)
PREp(getEq(keEG), 0:4, glmx$fitted.values/100, glmy$fitted.values/100)

kequate documentation built on April 13, 2022, 9:06 a.m.