Note that all the above scores are based on appropriate age groups. Back to Top 6. An IQ score is a standardized score that has been compared to an age appropriate normative sample. IQ scores have a mean of 100 and a standard deviation of 15. IQ scores are more easily interpreted when considering their percentile equivalents.
Percentiles express the relative position in the normative sample.
The percentile equivalent for an IQ score of 100 is 50. The percentile equivalent of an IQ score of 115 is 84, and that of an IQ score of 130 is 97.7. Back to Top 7. Subtest scores can be prorated to obtain a full scale score. The more subtests that are included in the prorated estimate, the more reliable the IQ score will be.