During the classification tree construction process, you are determining how to split the 8 datapoints provided below using one of the two predictor variables, X1 and X2. Express all answers rounded to four decimal places, but use unrounded values in all calculations.

x1	x2	y
8.7	3.6	0
1.2	3.3	1
4.9	8.9	1
3.2	4.5	0
2.9	3.2	1
9.2	4.3	1
9.7	6.2	1
2.3	8	0

Analyze the possible split points for X11 by filling in the table below.

1. Identify the possible split points.
2. Count the number of 0s and 1s in each branch of the possible splits.
3. Calculate the Gini index for each branch of the possible splits.
4. Calculate the combined Gini index for each possible splits.

Information about the possible split points for X22 is provided for you in the table below.Determine the optimal split.

1. What is the minimum Gini index overall?
2. Which variable would be split?
3. What split point would be used for the logical test of this new decison node?
   • X11
   • X22

Split Point	# of 0s Left Branch	# of 1s Left Branch	# of 0s Right Branch	# of 1s Right Branch	Gini Index Left Branch	Gini Index Right Branch	Combined Gini Index
3.25	0	1	3	4	0	0.4898	0.4286
3.45	0	2	3	3	0	0.5	0.375
3.95	1	2	2	3	0.4444	0.48	0.4667
4.4	1	3	2	2	0.375	0.5	0.4375
5.35	2	3	1	2	0.48	0.4444	0.4667
7.1	2	4	1	1	0.4444	0.5	0.4583
8.45	3	4	0	1	0.4898	0	0.4286