DEAR ABBY: What, exactly, is a person's "IQ," and how is it determined? -- A STUDENT IN GREEN BAY, WIS.
DEAR STUDENT: "IQ" stands for intelligence quotient, and it is determined by assigning a number to the level of skills attained on a standardized test. This number, sometimes called the "mental age" or M.A., is divided by the chronological age (C.A.) and then multiplied by 100. The total reflects one's comparison to a standardized group of this age.
For educational purposes, the IQ scores are categorized as follows: 125 to 140 or higher -- gifted; 115 or higher -- highly intelligent; 100 -- average.
Educable: An IQ of 50 to 75. One who can be educated academically to the level of an average child of 9 to 11 years of age, can socially adjust to family and home, and can occupationally support themselves totally or partly.
Trainable: An IQ of 25 to 50. One who can be trained to perform self-care skills such as dressing, feeding and toilette, can socially adjust to the home and neighborhood, and can gain some degree of ability such as routine tasks within the home or in a sheltered environment under supervision.
A person with an IQ under 25 usually requires nursing care, and is considered totally dependent.