Understanding IQ Percentiles
IQ percentiles help understand how an individual's intelligence quotient compares to the general population. The score follows a normal distribution with a mean of 100 and a standard deviation of 15.
What is an IQ Percentile?
An IQ percentile indicates the percentage of the population that scores below a given IQ score. For example, if you're in the 75th percentile, you score higher than 75% of the population.
The Normal Distribution of IQ Scores
Mean: 100 IQ points
Standard Deviation: 15 points
68% Range: 85-115
99.7% Range: 55-145
Interpreting IQ Classifications
IQ scores are typically classified into different categories based on statistical distribution:
- Very Superior (130+): Top 2.2% of the population
- Superior (120-129): Next 6.7%
- High Average (110-119): Next 16.1%
- Average (90-109): Middle 50%
- Low Average (80-89): Next 16.1%
- Borderline (70-79): Next 6.7%
- Extremely Low (Below 70): Bottom 2.2%
Factors Affecting IQ Scores
- Environmental Factors: Education quality, socioeconomic status, and early childhood experiences
- Physical Health: Nutrition, sleep quality, and overall wellness
- Test Conditions: Time of day, stress levels, and testing environment
- Practice Effects: Familiarity with similar tests and problem-solving methods