By using some preprocessing techniques, such as
visualization, we can get some primary useful
knowledge. For example, using Knim, which is an open
source data mining system from university of Konstanz,
Germany, we visualized students' data [6]. From this
visualization some useful knowledge has been drawn
about the attributes before applying data mining
methods. By using histogram of the data as in graph
(figure 4.1), we discovered that attendance, students'
GPAs, and lab grades has a positive relationship with
the final grade. However, e-learning facilities such as erecourses
used by student, exercises and assignment
hardly affected the final grade of student.