Mental retardation is one of several disabilities that is federally legislated in the idea. *if you are not me, look for in-depth for this section, unless you"ve taken psyc*3250. Overview norm-referenced tests = compared to a speci c reference group (esp. by age or grade level) standardization sample raw or obtained scores and derived scores. Types of scores standard score mean and standard deviation. Technical characteristics validity and reliability standard error of measurement. James mckeen cattell provided the early interest in measuring intelligence based on various de nitions. Rst to use the term mental test viewed intelligence as a combination physical + perceptual + mental. Spearman used factor analysis to propose a two-factor theory of intelligence two-factors general factor (g): present in all intellectual activities speci c factors (s): strengths dependent on the type of intellectual ability. Rst to propose multiple, separate forms of intelligence.