A male child of 15 years with a mental age of 9 years has an IQ of:
IQ = Mental age x 100/Chronological age =So, in this case, IQ = 9 x 100/15 = 60 Degree IQ level Mild 51-70 Moderate 36-50 Severe 21-35 Profound 0-20
50
60
70
80
Abnormalities of Development