The correct answer is Intelligence. Basel Age is the mental age level at which all the items on an intelligence test can be creditably passed. Basal age represents the highest level, on a test standardized in units corresponding to mental age or age-equivalents, below which it can be assumed that all items would be answered correctly. If a basal is not obtained, testing moves back to successively lower blocks until a basal is established. Ceiling Age: The lowest year level at which the examinee fails all the subtests of the scale. Mental Age: Mental age is computed by adding to his basal age, the number of months credit received for passing each subtest up to his ceiling age. Mental Age= basal age + credit (until ceiling age)