There's been many posts about figuring out the percentile of someone's score given the mean and SD. Hope this could settle the confusion once and for all. Here's a calculator for percentile: http://bayes.bgsu.edu/nsf_web/jscript/normal_cdf/normal_icdf.htm On the left, put in the mean and SD. On the right, under PROBABIILITY, input the percentile in decimle points. Like .90 for 90th%tile, .30 for 30th%tile then click COMPUTE X, it will tell you the score that corresponds to the percentile you input. For exmple, COMLEX mean 500, SD 79, using probabilty .90, then x = 601. So a 601 corresponds to a 90th%tile.