This function works depending on the package ggplot2 that allow to generate such graph. If the package ggplot2 is not
installed, the this function ask the user to install it. After install, load the package and show the graph.
A TPR vs FPR graph show the precision of a rule. Quality rules has big TPR values and small FPR values.
Big values of both quality measures indicates that the rule is too much general and it is too obvious.
Small values of both indicates that the rule is too much specific and it would be an invalid rule.