What Is Gini Index?

Table Of Contents:

  1. Introduction To Gini Index.
  2. Formula & Calculation.
  3. Gini Index In Decision Tree.
  4. Properties Of Gini Index.
  5. Weighted Gini Index.
  6. Gini Index Vs Entropy.
  7. Splitting Criteria and Gini Index.
  8. Advantages and Limitation Of Gini Index.
  9. Practical Implementation.
  10. Real-World Examples
  11. Advanced Topics

(1) Introduction To Gini Index.

Definition Of Gini Index

  • In the context of decision trees, the Gini Index is a metric used to evaluate the purity of a split or node.
  • It quantifies the probability of incorrectly classifying a randomly chosen element from the dataset if it were labeled randomly according to the class distribution.

Range Of Gini Index

Formula For Gini Index:

Example Of Gini Index:

After Splitting The Dataset Calculate The Gini Index:

(2) How Gini Index Used In Decision Trees ?

  • The Gini Index is a critical component of decision trees, particularly in the CART (Classification and Regression Trees) algorithm.
  • It is used to determine the “impurity” or “purity” of a node and helps in selecting the best feature to split the data at each step.
  • In a decision tree, we aim to split the data in such a way that the resulting nodes (subsets) are as pure as possible (i.e., most of the data in the node belongs to a single class).

(3) Key Differences Between Gini Index & Entropy.

(3) Advantages and Disadvantages Of Gini Index

Advantages:

Limitation:

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