19
Entropy-Based Automatic Decision Tree
Construction
Node 1
What feature
should be used?
What
values?
Training Set S
x1=(f11,f12,…f1m)
x2=(f21,f22, f2m)
.
.
xn=(fn1,f22, f2m)
Quinlan
suggested information gain in his ID3
system
and
later the gain ratio, both based on entropy.