Dull category
Terman claimed that different IQ scores correspond to different categories of intelligence, as shown below:
Under 70 - Feeble-mindedness
70 - 79 - Borderline deficiency
80 - 89 - Dullness
90 - 109 - Normal or average intelligence
110 - 119 - Superior intelligence
120 - 140 - Very superior intelligence
Over 140 - Genius or near genius
Thus, a score of 84 represents an individual in the dull category.
Terman calculated IQ by dividing a person's mental age by their chronological age.