In reviewing the split of data, Maggie notes among the 15 cases, 2 belong to Class 1 and the remaining to Class 0. What is the Gini index for the cases and is it pure or impure?
A) 0.00 default because it is under 0.5 and pure.
B) 0.23 is closer to 0 implying relative purity.
C) 0.27 is at the halfway point is not considered pure.
D) 0.77 is over the 0.5 level and is impure.

Question

Quizplus · Accepted Answer

The Gini index is calculated as 1 - sum(p_i^2) where p_i is the proportion of class i. For 2 classes with 2 in Class 1 and 13 in Class 0, the Gini index is 1 - ((2/15)^2 + (13/15)^2) = 0.23. This value is closer to 0, indicating relative purity, but not absolute purity.

In Reviewing the Split of Data, Maggie Notes Among the 15