What sort of scores are used for the WAIS?

• A. Percentile scores
• B. T-scores
• C. Standard Scores m=100 sd=15
• D. Z-scores

Answer: (C)

Scores on the WAIS are reported as standard scores with a mean of 100 and a standard deviation of 15. This creates a common, interpretable scale so you can judge how far a person’s performance is from the average and compare across ages and tests. The overall index scores and the full-scale IQ use this 100±15 distribution, with higher or lower values indicating above- or below-average performance relative to age peers. Subtests, by contrast, use scaled scores with a mean of 10 and an SD of 3, but the main WAIS interpretation relies on the standard scores of 100 and 15. Percentile ranks can be derived from these scores for description, but the primary scoring format is the standard score with mean 100 and SD 15.