Mean intelligence quotient is considered to be a score of 100, signifying this as the average outcome for an individual of so-called normal intellect. This is sometimes referred to as the fiftieth percentile. About half of the population scores within the mean range of 90 to 109. An IQ of between 80 and 89 is considered a low average, while a 10 point deviation above the mean range is termed high average from 110 to 119.
Intelligence quotient scores falling below 80 are classified as low. If the results are between 70 and 79, a borderline designation is used, while numbers 69 and under are considered extremely low. Individuals with IQ's in this range typically face cognitive challenges.
Any score above 120 earns the accolade of superior, while extremely superior IQ's must exceed 130 by traditional definition. Individuals whose IQ's are 120 or higher tend to populate occupational fields such as accounting, teaching and pharmacy, while their even brighter peers above 130 often comprise engineers and surgeons.