# plot.pwrrasch: Plot Statistical Power Curve In pwrRasch: Statistical Power Simulation for Testing the Rasch Model

## Description

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

## Usage

 ```1 2 3 4``` ```## 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:

• `type` The following values are possible: `"p"` for points, `"l"` for lines, `"b"` for both point and lines

• `pch` see points

• `lty` Line types can be specified as an integer (`0` = blank, `1` = solid, `2` = dashed, `3` = dotted, `4` = dotdash, `5` = longdash, `6` = twodash)

• `lwd` Positive numbers indicating line widths

• `legend` Either the x and y coordinates to be used to position the legend or keyword from the list `"bottomright"`, `"bottom"`, `"bottomleft"`, `"left"`, `"topleft"`, `"top"`, `"topright"`, `"right"` and `"center"`

• `bty` Allowed values are "o" (draw box around legend) and "n" (do not draw box around legend).

## 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

 ``` 1 2 3 4 5 6 7 8 9 10 11 12``` ```## 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) ```

pwrRasch documentation built on May 1, 2019, 10:37 p.m.