Figure 3.1: Parallel coordinate plot.
the central body of the distribution. The lower end of the box is at the 25-th
percentile of the distribution, the top of the box is at the 75-th percentile of the
distribution. So the box encompasses the central 50 percent of the distribution. In
addition a center line is drawn at the median.
The attribute labeled ”class” is a nominal attribute that has only three possible
values. The PMF plot for a nominal attribute is a bar chart in which the length of
each bar indicates the number of instances for a given value. So in this case there
are three bars corresponding to the three possible values for the attribute class.