Page 178 - DEDU504_EDUCATIONAL_MEASUREMENT_AND_EVALUATION_ENGLISH

Educational Measurement and Evaluation

Notes testee is credited with all items up through the age level at which he passes all. This is called the
basal year. He is also credited with all items passed above the basal year. The sum of his basal plus
the other credits, in terms of months, is his mental age.
Mental age norms are also used with scales that are not arranged according to age levels. These
are point scales that yield a score usually based on the number of items correctly answered. By
means of a table of norms provided for the particular test being used, it is possible to assign an
individual an age rating. Thus, on a point scale, an individual who, regardless of chronological
age (CA), earns a score equal to the norm of the ten-year-old population sample, will have a
mental age (MA) of ten, as determined by that test.
In determining mental age, whether by using an age scale or a point scale, an individual’s
performance on a standardized series of test items is being compared with the performance of
the average group of a representative sample at successive age levels. Hence, we define mental
age as the level of development in mental ability expressed as equivalent to the chronological
age at which the average group of individuals reach that level. For example, a child having an
MA of eight, has reached the level of the average group of eight-year-olds in the standardization
group.
At this point, our concern is only to define and clarify the mental age concept. There are several
important psychological and measurement problems connected with this concept that are
explained at several appropriate points in later sections.

In giving the test, the examiner continues upward in the scale until an age level is
reached at which the individual fails all items. This is called the terminal year.

13.1.4 Intelligence Quotient
The intelligence quotient, the ratio of an individual’s mental age to his chronological age, is
found by the formula :
MA
IQ = ( )100
CA
The ratio is multiplied by 100 to remove the decimal.
An individual’s IQ indicates rate of mental development or degree of brightness. If mental development
keeps pace with one’s life age, the quotient is 100. If mental development lags, or is accelerated,
the quotient will be less than or greater than 100, depending upon the degree of retardation or
acceleration.
It is clear that mental age alone does not adequately represent an individual’s mental capacity;
for persons of different, at times widely different, chronological ages may and do reach the same
mental age at a given time. One of the values of the IQ, therefore, is to reflect these age differences;
hence it is defined in terms of rate of mental development and, as an attribute, degree of brightness.
In his volume accompanying the 1916 Stanford-Binet scale, Terman included a table showing the
percentage of children at each of a number of IQ levels, each of which he gave a name; for
instance, dull, normal, very superior. An individual whose test performance is normal for his
chronological age earns an IQ rating of 100.

IQ range Terman’s categories

80-89 dullness
90-109 average intelligence
110-119 superior intelligence
120-140 very superior intelligence

172 LOVELY PROFESSIONAL UNIVERSITY