 
WJR Frequency Table: 14 Subtests
Required
Difference Between Single Scores and Mean Score at 5% Level of
Statistical Significance and Frequencies of Such Differences 

Average of 14 Subtests 

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 
Picture Vocabulary 
15.60 
32 
29 
24 
20 
17 
15 
13 
Analysis/Synthesis 
13.49 
33 
29 
24 
20 
17 
15 
13 
Visual Auditory Learning 
12.06 
35 
29 
23 
18 
16 
14 
12 
Memory for Words 
19.38 
34 
30 
25 
21 
18 
16 
15 
Cross Out 
20.86 
32 
30 
25 
20 
18 
16 
14 
Sound Blending 
15.33 
33 
30 
24 
20 
18 
16 
14 
Picture Recognition 
17.73 
37 
33 
27 
23 
20 
16 
15 
Oral Vocabulary 
13.73 
28 
25 
21 
17 
15 
13 
12 
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+[(K2)/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 WJR standardization data and for his kind permission to post these tables. 
Woodcock, R. W., & Mather, N. (1989). WJR Tests of Cognitive Ability Standard and Supplemental Batteries: Examiner's Manual. In R. W. Woodcock &
M. B. Johnson, WoodcockJohnson PsychoEducational BatteryRevised. Chicago: Riverside Publishing Co. All rights reserved. 
