Normal IQ Range for Intelligence
By Inderbir Kaur Sandhu, Ph.D
How do I compare my child's score to what is normal or the normal range? Is there a normal range or are there multiple factors that affect it?
I would assume that you mean normal range for intelligence testing
scores. Yes, there is a normal range and if it deviates from the norm,
the main factor affecting it would be the cognitive ability and
functioning. On the Wechsler's tests, the lowest score would be 40 and
highest is 160.
The simple graph below shows the range and distribution of IQ scores in
a normal IQ curve:
Today, an IQ score is compared among people of the same age or age
category and assumes that IQ is normally distributed. “Normally
distributed” means that the average (which is the mean score) is 100 and
that the standard deviation is about15. (However, please note that a
standard deviation of 15 may vary with different IQ tests).
A standard deviation is a measure of the spread of the sample from the
mean, which is about 2/3 of a population to 1 standard deviation. Thus,
as shown in the graph, about 95% of the population will be within 2
standard deviations from the mean (an IQ range of 70-130).
Hope the above has been helpful in your understanding. Good luck!