New listing UCLA BRUINS ADIDAS 1/4 ZIP POLO SHIRT (LRG) NW/TAGS SKY BLUE W/SEWN LOGOS.
It compares people of the same age or age category and assumes that IQ is normally distributed, that the average (mean) is 100 and that the standard deviation is something like 15 (IQ tests sometimes differ in their standard deviations).
Ever since the first IQ tests emerged, attempts to classify IQ have followed. While different test publishers utilize different scoring systems, for many modern IQ tests the average (or mean) score is set at 100 with a standard deviation of 15 so that scores conform to a normal distribution curve. 1  68 percent of scores fall within one standard deviation of the mean (that is, between 85 and 115)