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WJ-R Frequency Table: 14 Subtests
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Required
Difference Between Single Scores and Mean Score at 5% Level of
Statistical Significance and Frequencies of Such Differences |
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|
Average of 14 Subtests |
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Significance Level |
Cumulative % |
|
Cluster |
0.05 |
1% |
2% |
5% |
10% |
15% |
20% |
25% |
|
Memory for Names |
12.92 |
33 |
31 |
25 |
20 |
17 |
15 |
14 |
|
Memory for Sentences |
13.67 |
29 |
27 |
23 |
19 |
16 |
15 |
13 |
|
Visual Matching |
19.68 |
34 |
31 |
26 |
22 |
19 |
17 |
15 |
|
Incomplete Words |
17.68 |
32 |
29 |
25 |
21 |
18 |
16 |
14 |
|
Visual Closure |
22.94 |
36 |
32 |
27 |
22 |
19 |
17 |
16 |
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Picture Vocabulary |
15.60 |
32 |
29 |
24 |
20 |
17 |
15 |
13 |
|
Analysis/Synthesis |
13.49 |
33 |
29 |
24 |
20 |
17 |
15 |
13 |
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Visual Auditory Learning |
12.06 |
35 |
29 |
23 |
18 |
16 |
14 |
12 |
|
Memory for Words |
19.38 |
34 |
30 |
25 |
21 |
18 |
16 |
15 |
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Cross Out |
20.86 |
32 |
30 |
25 |
20 |
18 |
16 |
14 |
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Sound Blending |
15.33 |
33 |
30 |
24 |
20 |
18 |
16 |
14 |
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Picture Recognition |
17.73 |
37 |
33 |
27 |
23 |
20 |
16 |
15 |
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Oral Vocabulary |
13.73 |
28 |
25 |
21 |
17 |
15 |
13 |
12 |
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Concept Formation |
11.21 |
31 |
31 |
23 |
19 |
16 |
14 |
13 |
| Note:
The differences required for statistical significance are based on the
average standard errors of measurement across all ages and calculated with
the following formula provided by Davis (1959): Difference score = Z
SQRT[(SEmt^2)/K^2+[(K-2)/K](SEmi^2)], where Z is the normal curve value
associated with the desired significance level derived with the Bonferroni
correction for multiple comparisons, K is the number of tests in the
comparison, SEmt^2 is the sum of the squared standard errors of
measurement for all tests in the comparison, and SEmi^2 is the squared
standard error of measurement for the test of interest.
John and Ron thank Dr. Woodcock for his very generous granting of access to
portions of the WJ-R standardization data and for his kind permission to post these tables. |
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Woodcock, R. W., & Mather, N. (1989). WJ-R Tests of Cognitive Ability --Standard and Supplemental Batteries: Examiner's Manual. In R. W. Woodcock &
M. B. Johnson, Woodcock-Johnson Psycho-Educational Battery--Revised. Chicago: Riverside Publishing Co. All rights reserved. |
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