Item Characteristic Curve and Item Information Function: Item21

skill_level: 5 p: 0.979 skill_level: 4 p: 0.944 skill_level: 3 p: 0.862 skill_level: 2 p: 0.696 skill_level: 1 p: 0.458 skill_level: 1 iif: 0.248 skill_level: 0 p: 0.237 skill_level: 2 iif: 0.211 skill_level: 0 iif: 0.181 skill_level: 3 iif: 0.119 skill_level: -1 p: 0.102 skill_level: -1 p: 0.102 skill_level: -1 p: 0.102 skill_level: -1 iif: 0.092 skill_level: 4 iif: 0.0526 skill_level: -2 iif: 0.0387 skill_level: -2 p: 0.0403 skill_level: -2 p: 0.0403 skill_level: -2 p: 0.0403 skill_level: 5 iif: 0.0208 skill_level: -3 iif: 0.015 skill_level: -3 p: 0.0152 skill_level: -3 p: 0.0152 skill_level: -4 iif: 0.00562048710548 skill_level: -4 p: 0.00565243715123 skill_level: -4 p: 0.00565243715123 skill_level: -5 iif: 0.00208251682479 skill_level: -5 p: 0.00208687185895 skill_level: -5 p: 0.00208687185895
Plot of iif * skill_level


Distracter analysis table: Item21

The FREQ Procedure

Frequency
Col Pct
Table of A21 by Skill_level
A21(A21) Skill_level Total
-2 -1 0 1 2 3 4
A 3
25.00		 33
25.38		 115
21.58		 171
18.77		 158
18.27		 41
8.97		 2
0.83		 523
 
B 3
25.00		 49
37.69		 194
36.40		 274
30.08		 158
18.27		 47
10.28		 4
1.67		 729
 
C 5
41.67		 21
16.15		 43
8.07		 33
3.62		 8
0.92		 1
0.22		 0
0.00		 111
 
D 1
8.33		 27
20.77		 181
33.96		 433
47.53		 541
62.54		 368
80.53		 234
97.50		 1785
 
Total 12 130 533 911 865 457 240 3148
Frequency Missing = 37


Distractor analysis plot: Item21

Skill_level: 4 prob: 0.975 A21: D Skill_level: 3 prob: 0.805 A21: D Skill_level: 2 prob: 0.625 A21: D Skill_level: 1 prob: 0.475 A21: D Skill_level: -2 prob: 0.417 A21: C Skill_level: -1 prob: 0.377 A21: B Skill_level: 0 prob: 0.364 A21: B Skill_level: 0 prob: 0.34 A21: D Skill_level: 1 prob: 0.301 A21: B Skill_level: -2 prob: 0.25 A21: B Skill_level: -1 prob: 0.254 A21: A Skill_level: -2 prob: 0.25 A21: A Skill_level: -2 prob: 0.25 A21: A Skill_level: 0 prob: 0.216 A21: A Skill_level: -1 prob: 0.208 A21: D Skill_level: 2 prob: 0.183 A21: B Skill_level: 1 prob: 0.188 A21: A Skill_level: 2 prob: 0.183 A21: A Skill_level: -1 prob: 0.162 A21: C Skill_level: 3 prob: 0.103 A21: B Skill_level: 3 prob: 0.0897 A21: A Skill_level: -2 prob: 0.0833 A21: D Skill_level: 0 prob: 0.0807 A21: C Skill_level: 1 prob: 0.0362 A21: C Skill_level: 4 prob: 0.0167 A21: B Skill_level: 4 prob: 0.00833333333333 A21: A Skill_level: 2 prob: 0.00924855491329 A21: C Skill_level: 3 prob: 0.00218818380743 A21: C
Plot of prob * Skill_level = A21


Distractor analysis plot: Item21

KEY21
D