plot.r2Winsteps: Plot the test characteristic curve

In DJAnderson07/r2Winsteps: A package for interfacing between R and the Rasch modeling software Winsteps

Description

Plot the test characteristic curve

Usage

## S3 method for class 'r2Winsteps'
plot(ob, type = "TIF", rel = TRUE, theta = seq(-4, 4,
  0.1), itemSelect = NULL, colors = NULL, legend = TRUE, store = FALSE,
  grid = TRUE, gridCol = "gray80", ...)

Arguments

ob	Objects of class r2Winsteps
type	The type of plot to produce. Valid values are "TIF", "IIFs", "CSEM", "TCC", "ICCs" "ICP", "thresholds", and "ipDens". These correspond to, respectively, the test information function, item information functions, the conditional standard error of measure curves, the test characteristic curve, item characteristic curves, item-category probabilities, Thurstonion thresholds, and overlayed item and person densities. Note that ICP and Thresholds are only available for polytomous models. When specifying lty or lwd for "iDens", a vector (of length 2) must be supplied, corresponding to each distribution. Defaults to "TIF".
rel	When type == "TIF", should the distribution be shaded according to reliability? Defaults to TRUE and shades the distribution according to 0.8 and 0.7 reliabilities.
theta	Theta values from which the information function values are calculated from. Defaults to a sequence from -4 to 4 by 0.1. The limits of this range are used for the x-axes.
itemSelect	Items to be used in the plotting. Defaults to NULL, in which case all items will be used.
colors	Line colors for the plot. Defaults to NULL, in which case the colors match the defaults from ggplot.
store	Optional logical argument to return data used in plotting (not available for all plot types). For example, when store = TRUE and type = "TIF", information under the specified theta range will be returned.
grid	Optional grid for interpreting graphs. Defaults to TRUE, in which case the graph is produced with a grid.
gridCol	Optional color function for grid. Defaults to "gray80", in which case the graph is produced with a "gray80" color grid.
...	Additional arguments passed to plot.

DJAnderson07/r2Winsteps documentation built on Sept. 12, 2019, 1:06 a.m.