Calculation of Entropy o Entropy is a measure of uncertainty in the data Entropy(S)=∑ (i=1 to 1-1S/|S|*log2(|S|/|S ◆S= set of examples Si subset of s with value vi under the target attribute size of the range of the target attribute 1414 Calculation of Entropy ⚫ Entropy is a measure of uncertainty in the data ◆ S = set of examples ◆ Si = subset of S with value vi under the target attribute ◆ l = size of the range of the target attribute