PREp: Percent relative error
In jagonzalb/SNSequate: Standard and Nonstandard Statistical Models and Methods for Test Equating

Description Usage Arguments Details Value Author(s) References See Also Examples

This function calculates the percent relative error as described in Von Davier et al. (2004).

1	PREp(eq, p)

`eq`	An object of class `ker.eq` previously obtained using `ker.eq`.
`p`	The number of moments to be calculated.

PREp (when equating form X to Y) is calculated as

100*(μ_p(e_Y(X))-μ_p(Y))/μ_p(Y)

where μ_p(Y)=∑_k(y_k)^p*s_k and μ_p(e_Y(X))=∑_j(e_Y(x_j))^p*r_j. Similar formulas can be found when equating from Y to X.

A matrix containing the PREp for both X to Y (first column) and Y to X (second column) cases.

Jorge Gonzalez B. jgonzale@mat.puc.cl

Gonzalez, J. (2014). SNSequate: Standard and Nonstandard Statistical Models and Methods for Test Equating. Journal of Statistical Software, 59(7), 1-30.

Von Davier, A., Holland, P., and Thayer, D. (2004). The Kernel Method of Test Equating. New York, NY: Springer-Verlag.

ker.eq

#Example: Table 7.5 in Von Davier et al. (2004)

data(Math20EG)
mod.gauss<-ker.eq(scores=Math20EG,kert="gauss", hx = NULL, hy = NULL,degree=c(2, 3),design="EG")
PREp(mod.gauss,10)