Another use of the repeated association technique in terms of the enrichment of concepts, which was given as the aim of learning and teaching in the last chapter. It is useful to compare the student's associa- tions to a concept at the beginning of a course with those that he makes at the end. Most people have a general idea about the meaning of a concept, but the better a person understands it the richer is its connotation to him. For instance, most people know what is meant by an and could readily work out a football team's goal average or mean average by adding the goals it had scored and dividing by the number of matches played. Without a course in statistics, however, they might not be aware of the difference between arithmetic means, geometric means, and harmonic means. Nor might they be aware of the mathe matical definition of an arithmetic mean as that value in a frequency distribution from which the algebraic sum of the deviations equals zero Similarly, they might not be aware of the place of the arithmetic mean in a moment's system, where it is seen as a fulcrum and related to measures of variance, skewness, and kurtosis.