It is important to notice that gathering information and
pre-processing data were two very important tasks in this
work. In fact, the quality and the reliability of the used
information directly affects the results obtained. However, this
is an arduous task that involves a lot of time to do. Specifically,
we had to do the pick out of data from a paper and pencil
survey and we had to integrat data from three different sources
to form the final dataset.