SAS Output

Item Characteristic Curve and Item Information Function: Item20

Plot of iif * skill_level

Distracter analysis table: Item20

The FREQ Procedure

Frequency Col Pct

Table of A20 by Skill_level
A20(A20)	Skill_level							Total
A20(A20)	-2	-1	0	1	2	3	4	Total
A	0 0.00	29 22.83	53 9.94	99 10.89	52 6.01	9 1.97	0 0.00	242
B	3 33.33	38 29.92	110 20.64	98 10.78	41 4.74	5 1.10	1 0.42	296
C	3 33.33	31 24.41	54 10.13	37 4.07	9 1.04	1 0.22	0 0.00	135
D	3 33.33	29 22.83	316 59.29	675 74.26	763 88.21	441 96.71	239 99.58	2466
Total	9	127	533	909	865	456	240	3139
Frequency Missing = 37

Distractor analysis plot: Item20

Plot of prob * Skill_level = A20

Distractor analysis plot: Item20

KEY20
D