| rim {irtoys} | R Documentation |
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 |
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 |
Author(s)
Ivailo Partchev, using theory and C code by Gunter Maris
See Also
Examples
rim(Scored, items=2)