Intelligence Quotient (IQ). IQ refers to mental age divided by chronological age, and multiplied by 100.
Distribution of IQ score in a population-
IQ scores are distributed in such a way that the IQ scores of most people tend to fall in the middle range of the distribution. Most people show a moderate level of performance i.e. in the middle range of the distribution.
Very few are on extremes showing:
- Extreme high (excellent) performance (2.2%)
- Extremely low (very poor) performance (2.2%)
Frequency distribution of IQ Scores – tends to approximate a bell-shaped curve. It is called Normal Curve where the curve does not touch the x-axis. There is no one with 0 IQ.