My 12 year-old child has been grade skipped one year and recently sat an assessment (for school entry) that tests bright children (the top 10%) on multiple subjects (maths, problem solving, comprehension, spelling and literacy). The lowest score my child received was in the top 7%ile. Does anyone know what the percentile might be had it been a test for all abilities and of the same age? Is there a maths equation to work out a bell curve over a bell curve??

Thank you.