plot method for DIF
# S3 method for DIF_stats
plot(x, items = NULL, itemsX = items,
itemsY = items, ...)
object produced by DIF
character vector of item id's for a subset of the plot. Useful if you have many items. If NULL all items are plotted.
character vector of item id's for the X axis
character vector of item id's for the Y axis
further arguments to plot