What is mental redardation?

Mental retardation is defined as having an IQ below 70. For mild MR, scores are between 55 and 69. For moderate MR, IQ scores are between 40 and 55. In the case of severe MR, scores are between 25 and 40. And for profound MR, IQ scoring is below 25. (An IQ of 100 is average, with the norms going from 85-115 for approximately two thirds of the population. (Between 70 and 85, the term "borderline intellectual function" is designated.)
Mental retardation is defined as having an IQ below 70. For mild MR, scores are between 55 and 69. For moderate MR, IQ scores are between 40 and 55. In the case of severe MR, scores are between 25 and 40. And for profound MR, IQ scoring is below 25. (An IQ of 100 is average, with the norms going from 85-115 for approximately two thirds of the population. (Between 70 and 85, the term "borderline intellectual function" is designated.)