plot.pwrrasch {pwrRasch}R Documentation

Plot Statistical Power Curve

Description

Generic plot function for the pwrrasch object, which plots the statistical power curve relating statistical power to sample size

Usage

## S3 method for class 'pwrrasch'
plot(x, plot.sig.level = TRUE, type = c("b", "b"),
  pch = c(19, 17), lty = c(1, 3), lwd = c(1, 1), legend = "topleft",
  bty = "o", ...)

Arguments

x

pwrrasch object.

plot.sig.level

If TRUE, nominal significance level is plotted.

type

Vector indicating type of plot for the statistica power curve and the type 1 risk curve.

pch

Vector indicating plotting symbol for the statistical power curve and the type 1 risk curve.

lty

Vector indicating line type for the statistical power curve and the type 1 risk curve.

lwd

Vector indicating line width for the statistical power curve and the type 1 risk curve.

legend

Location of the legend. If FALSE, legend is omitted.

bty

Type of box to be drawn around the legend.

...

Additional arguments affecting the summary produced.

Details

Graphical parameters are:

Author(s)

Takuya Yanagida takuya.yanagida@univie.ac.at, Jan Steinfeld jan.steinfeld@univie.ac.at

References

Kubinger, K. D., Rasch, D., & Yanagida, T. (2009). On designing data-sampling for Rasch model calibrating an achievement test. Psychology Science Quarterly, 51, 370-384.

Kubinger, K. D., Rasch, D., & Yanagida, T. (2011). A new approach for testing the Rasch model. Educational Research and Evaluation, 17, 321-333.

Examples

## Not run: 

# item parameters
ipar2 <- ipar1 <- seq(-3, 3, length.out = 20)
# model differential item function (DIF)
ipar2[10] <- ipar1[11]
ipar2[11] <- ipar1[10]
# simulation for b = 100, 200, 300, 400, 500
simres <- pwr.rasch(seq(100, 500, by = 100), ipar = list(ipar1, ipar2))
plot(simres)

## End(Not run)

[Package pwrRasch version 0.1-2 Index]