|
| |
WJ-R Frequency Table: 7
Subtests
|
Required Difference Between Single Scores and Mean Score
at 5% Level of Statistical Significance and Frequencies of Such
Differences |
|
|
Average of 7 Subtests |
|
|
|
Significance Level |
Cumulative % |
|
Cluster |
|
0.05 |
1% |
2% |
5% |
10% |
15% |
20% |
25% |
|
Memory for Names |
|
11.99 |
33 |
30 |
24 |
20 |
17 |
15 |
14 |
|
Memory for Sentences |
|
12.56 |
29 |
27 |
23 |
19 |
17 |
15 |
13 |
|
Visual Matching |
|
17.28 |
34 |
31 |
25 |
21 |
19 |
16 |
15 |
|
Incomplete Words |
|
15.69 |
31 |
29 |
27 |
20 |
17 |
15 |
14 |
|
Visual Closure |
|
19.90 |
34 |
31 |
26 |
22 |
19 |
17 |
15 |
|
Picture Vocabulary |
|
14.05 |
29 |
27 |
23 |
19 |
17 |
14 |
13 |
|
Analysis/Synthesis |
|
12.42 |
32 |
39 |
24 |
19 |
17 |
15 |
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. |
|
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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