An item with medium item difficulty and low item discrimination is to be plotted.

(a) Use the function iccplot to plot an item characteristic curve of an item with medium item difficulty and low item discrimination.

(b) From the graph it can be seen that the probability of correct response will be between 0.2 and 0.8 over the range of ability shown. The item characteristic curve will be nearly linear over the range of ability employed.

(c) After you have studied the curve, make sure to click the R console window to make it current and to type in a new command line.

(d) The next graph will be plotted in a new graphics window.