Item Analysis Sample Output | Miscellaneous

Item Analysis Sample Output

          ****TEST STATISTICS****


NUMBER OF EXAMINEES 133

TOTAL SCORE:
MEAN 18.83
VARIANCE 46.29
STANDARD DEVIATION 6.80
KR-20 RELIABILITY .8359
S.E. OF MEASUREMENT 2.7566


An overview of item analysis statistics appears in
Osterlind, Steven J. Constructing Test Items. 2nd ed.
Boston: Kluwer Academic Publishers, 1998.

G L O S S A R Y

DIF: DIFFICULTY - the proportion of examinees answering the item correctly
RPB: Point-biserial correlation between item and total test score
CRPB: Corrected RPB - RPB between item and total score not including the present item
CON: Confidence limits on CRPB
RBIS: Biserial correlation between item and total test score
CRBIS: Corrected RBIS
IRI: Item reliability index - RPB times square root of DIF times one minus DIF
N: Number of examinees in group
INV: Number of examinees not providing a valid response to this item
NF: Number of examinees not finishing the test from this item onwards
OMIT: Number of examinees omitting this item
*: indicates the correct answer (keyed response)
HIGH: Approximately 27.0% of the total group scoring highest on the total test
LOW: Same proportion as 'HIGH' having lowest scores

TEST SCORE MEANS: Means on the total test for the individuals giving the indicated response to this item
DISCRIMINATING POWER: The difference between the proportions of the HIGH and LOW groups giving this response
STANDARD ERROR OF D.P.: Standard error of discriminating power

Following the numerical report of the item analysis, plots are provided which illustrate the relationship
between achievement or ability as measured by the total test and success on a given item.
These plots are only provided if there is a sufficient number of cases.


 ITEM   1 deleted from test

ITEM 8: DIF= .263, RPB= .367, CRPB= .302 (95% CON= .139, .449)
RBIS= .494, CRBIS= .407, IRI= .161
GROUP N INV NF OMIT A B* C D
TOTAL 133 1 0 1 .23 .26 .14 .37
HIGH 37 0 .24 .43 .11 .22
MID 56 0 .30 .27 .12 .30
LOW 40 1 .10 .10 .17 .60
TEST SCORE MEANS 19.87 23.00 17.83 15.92
DISCRIMINATING POWER .14 .33 -.07 -.38
STANDARD ERROR OF D.P. .09 .10 .08 .11

ITEM 9: DIF= .053, RPB= .234, CRPB= .201 (95% CON= .032, .359)
RBIS= .486, CRBIS= .418, IRI= .052
GROUP N INV NF OMIT A* B C D
TOTAL 133 16 0 16 .05 .20 .17 .46
HIGH 37 1 .14 .22 .19 .43
MID 56 6 .04 .12 .21 .52
LOW 40 9 .00 .28 .10 .40
TEST SCORE MEANS 25.57 19.27 18.87 18.90
DISCRIMINATING POWER .14 -.06 .09 .03
STANDARD ERROR OF D.P. .06 .10 .08 .11

ITEM 12: DIF= .511, RPB= .382, CRPB= .309 (95% CON= .146, .455)
RBIS= .479, CRBIS= .387, IRI= .191
GROUP N INV NF OMIT A* B C D
TOTAL 133 1 0 1 .51 .14 .18 .17
HIGH 37 0 .76 .03 .05 .16
MID 56 0 .54 .11 .20 .16
LOW 40 1 .25 .28 .28 .17
TEST SCORE MEANS 21.37 14.44 16.08 18.32
DISCRIMINATING POWER .51 -.25 -.22 -.01
STANDARD ERROR OF D.P. .11 .08 .09 .09

ITEM 13: DIF= .278, RPB= .100, CRPB= .034 (95% CON= -.137, .203)
RBIS= .133, CRBIS= .045, IRI= .045
GROUP N INV NF OMIT A B C D*
TOTAL 133 16 0 16 .14 .17 .29 .28
HIGH 37 3 .14 .14 .32 .32
MID 56 6 .11 .21 .32 .25
LOW 40 7 .17 .15 .22 .28
TEST SCORE MEANS 16.94 18.48 19.26 19.92
DISCRIMINATING POWER -.04 -.01 .10 .05
STANDARD ERROR OF D.P. .08 .08 .10 .10

ITEM 34: DIF= .459, RPB= .480, CRPB= .407 (95% CON= .255, .540)
RBIS= .603, CRBIS= .511, IRI= .239
GROUP N INV NF OMIT A B* C D
TOTAL 133 1 0 1 .12 .46 .24 .17
HIGH 37 0 .00 .78 .14 .08
MID 56 0 .14 .43 .21 .21
LOW 40 1 .20 .20 .38 .20
TEST SCORE MEANS 14.69 22.38 16.25 16.61
DISCRIMINATING POWER -.20 .58 -.24 -.12
STANDARD ERROR OF D.P. .07 .11 .10 .08

ITEM 35: DIF= .376, RPB= .437, CRPB= .366 (95% CON= .209, .505)
RBIS= .558, CRBIS= .467, IRI= .212
GROUP N INV NF OMIT A B C D*
TOTAL 133 2 0 2 .26 .10 .25 .38
HIGH 37 0 .11 .00 .19 .70
MID 56 1 .30 .14 .27 .27
LOW 40 1 .35 .12 .28 .22
TEST SCORE MEANS 16.26 15.46 17.70 22.66
DISCRIMINATING POWER -.24 -.12 -.09 .48
STANDARD ERROR OF D.P. .10 .06 .10 .11

ITEM 36: DIF= .639, RPB= .485, CRPB= .414 (95% CON= .263, .546)
RBIS= .622, CRBIS= .532, IRI= .233
GROUP N INV NF OMIT A B C D*
TOTAL 133 0 0 0 .14 .11 .11 .64
HIGH 37 0 .05 .00 .03 .92
MID 56 0 .16 .11 .09 .64
LOW 40 0 .20 .20 .22 .38
TEST SCORE MEANS 15.47 13.79 13.73 21.31
DISCRIMINATING POWER -.15 -.20 -.20 .54
STANDARD ERROR OF D.P. .08 .07 .08 .11

ITEM 37: DIF= .391, RPB= .041, CRPB= -.031 (95% CON= -.200, .140)
RBIS= .052, CRBIS= -.039, IRI= .020
GROUP N INV NF OMIT A B* C D
TOTAL 133 2 1 1 .21 .39 .22 .17
HIGH 37 0 .19 .41 .19 .22
MID 56 0 .25 .38 .21 .16
LOW 40 2 .17 .40 .25 .12
TEST SCORE MEANS 19.21 19.17 17.79 20.23
DISCRIMINATING POWER .01 .01 -.06 .09
STANDARD ERROR OF D.P. .09 .11 .09 .09


                                     PLOT OF TEST SCORE GROUPS (QUINTILES) BY ITEM DIFFICULTY    
The sizes of the quintile groups from 'Highest' to 'Lowest' are: 25 27 25 32 24


QUINTILE: ITEM 8 QUINTILE: ITEM 9
Highest- x Highest- x

4th- x 4th- x

3rd- x 3rd- x

2nd- x 2nd-x

Lowest- x Lowest-x
|----|----|----|----|----|----|----|----|----|----| |----|----|----|----|----|----|----|----|----|----|
DIFF=.0 .1 .2 .3 .4 .5 .6 .7 .8 .9 1.0 DIFF=.0 .1 .2 .3 .4 .5 .6 .7 .8 .9 1.0


QUINTILE: ITEM 12 QUINTILE: ITEM 13
Highest- x Highest- x

4th- x 4th- x

3rd- x 3rd- x

2nd- x 2nd- x

Lowest- x Lowest- x
|----|----|----|----|----|----|----|----|----|----| |----|----|----|----|----|----|----|----|----|----|
DIFF=.0 .1 .2 .3 .4 .5 .6 .7 .8 .9 1.0 DIFF=.0 .1 .2 .3 .4 .5 .6 .7 .8 .9 1.0


QUINTILE: ITEM 34 QUINTILE: ITEM 35
Highest- x Highest- x

4th- x 4th- x

3rd- x 3rd- x

2nd- x 2nd- x

Lowest- x Lowest- x
|----|----|----|----|----|----|----|----|----|----| |----|----|----|----|----|----|----|----|----|----|
DIFF=.0 .1 .2 .3 .4 .5 .6 .7 .8 .9 1.0 DIFF=.0 .1 .2 .3 .4 .5 .6 .7 .8 .9 1.0


QUINTILE: ITEM 36 QUINTILE: ITEM 37
Highest- x Highest- x

4th- x 4th- x

3rd- x 3rd- x

2nd- x 2nd- x

Lowest- x Lowest- x
|----|----|----|----|----|----|----|----|----|----| |----|----|----|----|----|----|----|----|----|----|
DIFF=.0 .1 .2 .3 .4 .5 .6 .7 .8 .9 1.0 DIFF=.0 .1 .2 .3 .4 .5 .6 .7 .8 .9 1.0




           ITEMS    1 TO   40                                                          
DISCRIMINATION X DIFFICULTY CHART

**************************************************************************************************************************
1.0* *
* *
* *
* *
.9* *
* *
* *
* *
.8* *
B * *
I * *
S * *
E .7* 15 *
R * 21 20 *
I * 32 17 *
A * 29 27 34 25 26 36 *
L .6* 23 *
* 35 24 *
* 40 38 *
C * 5 11 *
O .5* 9 8 12 28 *
R * 39 33 18 19 *
R * 10 *
E * *
L .4* 22 31 7 16 *
A * 4 14 3 6 *
T * *
I * 30 *
O .3* 2 *
N * *
* *
* *
.2* *
* *
* 13 *
* *
.1* *
* 37 *
* *
* *
.0**************************************************************************************************************************
.0 .1 .2 .3 .4 .5 .6 .7 .8 .9 1.0

D I F F I C U L T Y


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