**6.3 Average**

For concept S, attributes *A1,..., An* of S, and attribute quantifier function f, the ratio of the total attribute number of S with respect to *A1,..., An* and f and the cardinality of S is called the average of the value of S with respect to *A1,..., An* of *f*. The quantifying concept ⫷average⫸ is regarded as a function that has the same input data as that of ⫷total attribute number⫸ and that outputs the average of the value of S with respect to *A1,..., An* of *f*.
