rim: Item-total regressions for the Rasch vs. the interaction model
Description
Compare the item-total regressions fit by the Rasch model and
the interaction model, for one, several, or all items in the test.
Usage
rim(x, items = NULL, showData = FALSE, shade = 10, ncol = 3, ...)
Arguments
x
A matrix of scored responses (persons in rows, items in columns)
items
The items to plot (column numbers). If NULL, all items will be plotted
showData
If TRUE, the observed proportion correct at each sum score will
be shown on the plot. Default is FALSE (show only the regressions)
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.
ncol
When plotting multiple items, the user can suggest the number of
columns in the matrix of plots (up to 3, will be adjusted if necessary)
...
Any additional plotting parameters
Examples
Run this code# NOT RUN {
rim(Scored, items=2)
# }
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