PREp function

Percent Relative Error

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

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 $\mu(Y)$ and $\mu(eYx)$ respectively, the PRE for moment p is defined as

Returns

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

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.

Author(s)

bjorn.andersson@statistik.uu.se

kenny.branberg@stat.umu.se

marie.wiberg@stat.umu.se

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)