  In an earlier work we have used the Triangular Fuzzy Numbers (TFNs)as an
assessment tool of student skills.This approach led to an approximate
linguistic characterization of the students' overall performance, but it was
not proved to be sufficient in all cases for comparing the performance of two
different student groups, since tywo TFNs are not always comparable. In the
present paper we complete the above fuzzy assessment approach by presenting a
defuzzification method of TFNS based on the Center of Gravity (COG) technique,
which enables the required comparison. In addition we extend our results by
using the Trapezoidal Fuzzy Numbers (TpFNs) too, which are a generalization of
the TFNs, for student assessment and we present suitable examples illustrating
our new results in practice.
