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plot.imp

A plot method for the interaction model

Plot the item-total regressions fit by the interaction (or Rasch) model

## S3 method for class 'imp'
plot(x, items = NULL, shade = 10, highlight = -Inf,
  add = FALSE, main = "Item-total regression", label = FALSE, ...)

`x`	An object produced by function `interactionModel`
`items`	The items to plot (column numbers). If NULL, all items will be plotted
`shade`	The part of the probability mass for the sum scores to shade out, shown as percentage. Default is 10: shade the most extreme 10 Ignored when `add=TRUE`.
`highlight`	Cutpoint for the interaction parameter below which a regression line will be highlighted in red. Default is -Inf (do not highlight).
`add`	When `add=TRUE`, the graph is added to a plot, otherwise a new plot is started. Default is FALSE.
`main`	The main title of the plot, given that `add=FALSE`.
`label`	When `label=TRUE`, individual curves will be labeled with the item number.
`...`	Any additional plotting parameters

Ivailo Partchev, using theory and C code by Gunter Maris

plot(interactionModel(Scored), highlight=-.3)

A Collection of Functions Related to Item Response Theory (IRT)

v0.2.1

GPL (>= 2)

Authors

Ivailo Partchev [aut, cre], Gunter Maris [aut], Tamaki Hattori [ctb]

Initial release

2017-12-15