plot.ifile: Plotting Item Staistics

In Rwinsteps: Running Winsteps in R

Description

These are Rasch model plot methods for item response functions, item inforamtion functions, item error functions, the test response function, the test information function, and the test error function, where each applies to an object of the corresponding class. plot.ifile summarizes the items within an ifile by plotting each of these functions in succession.

Usage

## S3 method for class 'ifile'
plot(x, theta = seq(-4, 4, length = 100),
  subset = 1:nrow(x), ...)

## S3 method for class 'rirf'
plot(x, theta = x$theta, add = FALSE,
  xlab = expression(theta), ylab = "P(X)", main = "IRF",
  lwd = 2, col = "r", ...)

## S3 method for class 'riif'
plot(x, theta = x$theta, add = FALSE,
  xlab = expression(theta), ylab = "Information", main = "IIF",
  lwd = 2, col = "r", ...)

## S3 method for class 'rief'
plot(x, theta = x$theta, add = FALSE,
  xlab = expression(theta), ylab = "Standard Error",
  main = "IEF", lwd = 2, col = "r", ...)

## S3 method for class 'rtrf'
plot(x, theta = x$theta, xlab = expression(theta),
  ylab = "Total", main = "TRF", lwd = 2, ...)

## S3 method for class 'rtif'
plot(x, theta = x$theta, xlab = expression(theta),
  ylab = "Information", main = "TIF", lwd = 2, ...)

## S3 method for class 'rtef'
plot(x, theta = x$theta, xlab = expression(theta),
  ylab = "Standard Error", main = "TEF", lwd = 2, ...)

Arguments

x	for plot.ifile, an object of class “ifile”, otherwise, either an ifile or a vector of item locations
theta	optional vector of theta values over which the functions will be evaluated
subset	an index vector indicating the items to plot, as row numbers or item names if present in the ifile
xlab	the x-axis label, as a string, defaulting to expression(theta)
ylab	the y-axis label, as a string, with default depending on the method
main	the plot title, with default depending on the method
lwd	line width, as an integer, defaulting to 2
col	vector of line colors, where the default "r" indicates a selection from the rainbow. Recycled if necessary
add	boolean, with default FALSE, indicating whether or not to add to the current plot
...	Further arguments passed to plot.default

Author(s)

Anthony Albano [e-mail]

See Also

ifile

Examples

plot(ifile(-2:2))

Rwinsteps documentation built on May 2, 2019, 1:08 p.m.