The test consists of 45 questions. The number of questions that you answer correctly is benchmarked against a large comparison group - the norm group - to calculate your standard score on a ten point scale.
A percentile score range can be calculated from the standard score. A percentile score tells you how many people in the norm group had a lower result than you. For instance, a percentile score of 60 means that 60 percent of the test takers had a lower result than you, and 40 percent had an equal or higher.