It does not give accurate result when there is noise. To
remove the noise pre-processing technique has to be used.
To build decision tree, information gain is calculated for each
and every attribute and select the attribute with the highest
information gain to designate as a root node. Label the attribute
as a root node and the possible values of the attribute are
represented as arcs. Then all possible outcome instances are
tested to check whether they are falling under the same class or
not. If all the instances are falling under the same class, the
node is represented with single class name, otherwise choose
the splitting attribute to classify the instances.