If a student had a z score of 2.5 for IQ, whar is his actual IQ? The IQ mean is 100, and standard deviation is 15.
(IQ - 100)/15 = 2.5
IQ-100 = 37.5
IQ = 137.5
FYI: It corresponds to the 95.2% percentile. Only 4.8% are higher. That comes from the normal distribution formula.