Question:

See the answer

X1

X2

Y

1

1

0

1

2

1

2

1

1

2

2

0

2

3

1

3

3

1

 
Consider the above table of 6 observations. Values of X1 and X2 are used to predict the outcome Y. When Y is 1 the outcome is considered to be positive.
If in the process of making a decision tree X2 is considered as splitting feature and 2.5 is considered as splitting value and values less than 2.5 go to the left node. What will the Gini impurity of the split data be?