People with mental retardation in the U. 5 million, have historically been victimized both by their disability and by public prejudice and ignorance. Mental retardation is a lifelong condition of impaired or incomplete mental development. The vast programs for children with mental retardation of people in the United States have I.
80 and 120, with an I. To be diagnosed as having mental retardation, a person must have an I. Although all persons with mental retardation have significantly impaired mental development, their intellectual level can vary considerably. An estimated 89 percent of all people with retardation have I. 60 to 70 range is approximately the scholastic equivalent to the third grade. For the lay person or non-specialist, the significance of a low I. When a person is said to have a mental age of six, this means he or she received the same number of correct responses on a standardized I.