WIAT Norm-Referenced Score Interpretation and Reporting 1 — Questions and Answers
Question 1: What is the mean (average) standard score for the WIAT normative population?
- 50
- 85
- 100 (Correct answer)
- 115
Correct answer: 100
WIAT standard scores are norm-referenced with a mean of 100 and a standard deviation of 15, consistent with most individually administered achievement tests.
Question 2: What is the standard deviation of WIAT standard scores?
- 5
- 10
- 15 (Correct answer)
- 20
Correct answer: 15
WIAT standard scores have a standard deviation of 15, so a score of 115 is exactly one standard deviation above the mean of 100.
Question 3: A student earns a WIAT standard score of 115 on the Reading Composite. This score corresponds to approximately which percentile rank?
- 50th
- 68th
- 84th (Correct answer)
- 97th
Correct answer: 84th
A standard score of 115 is exactly one standard deviation above the mean of 100, which corresponds to approximately the 84th percentile.
Question 4: Which qualitative descriptor best applies to a WIAT standard score of 85?
- Average
- Borderline
- Low Average (Correct answer)
- High Average
Correct answer: Low Average
On the WIAT, standard scores of 80–89 are described as Low Average, placing the score below average but not in the Borderline range.
Question 5: What does a percentile rank of 50 on the WIAT indicate?
- The student answered 50% of items correctly
- The student performed better than 50% of same-age peers (Correct answer)
- The student is proficient in all academic areas
- The student scored exactly at the standard score mean
Correct answer: The student performed better than 50% of same-age peers
A percentile rank of 50 means the student scored at or above 50% of the normative reference group of the same age, not that they got 50% of items correct.
Question 6: Which type of WIAT score describes performance in terms of the typical age at which that level of achievement is normally observed?
- Standard score
- Percentile rank
- Age equivalent (Correct answer)
- Stanine
Correct answer: Age equivalent
Age equivalents express a student's performance as the age in the normative sample at which the average student earned that same raw score.
Question 7: A 95% confidence interval of 90–102 reported for a WIAT standard score means:
- The true score is guaranteed to fall between 90 and 102
- There is a 95% probability that the student's true score falls within this range (Correct answer)
- The student scored between 90 and 102 on 95% of subtests
- 95% of students in the norm group scored in this range
Correct answer: There is a 95% probability that the student's true score falls within this range
Confidence intervals reflect measurement error; a 95% confidence interval means there is a 95% probability that the interval contains the student's true score.
WIAT Norm-Referenced Score Interpretation and Reporting 1
What is the mean (average) standard score for the WIAT normative population?