In this tutorial, we will learn about the computing Information-Gain for Continuous-Valued Attributes.

First of all, lets see that what are continuous attributes?

Continuous attributes can be represented as floating  point variables. For example temperature, width, height, or weight of a body.

To calculate the split point is not a big deal. It is just a just a fun to find the split point. For example, we have the following data mentioned below;

How can we calculate the split point?

Income	Class
18	YES
45	NO
18	NO
25	YES
28	YES
28	NO
34	NO

Solution  to calculate the split point

Step 1:

First of all, we need to sort the data in ascending order. After sorting the data, data is shown in the table below.

Income	Class
18	YES
18	NO
25	YES
28	YES
28	NO
34	NO
45	NO

Step 2:

Find the midpoint of first two numbers and calculate the information gain

Split point = (18+25) / 2 = 21

  Infoincome<21(D) = 2/7(I(1,1)) + 5/7(I(2,3))

  = 2/7(-1/2(log2(1/2)) – 1/2(log2(1/2))+5/7(-2/5(log2(2/5)) – 3/5(log2(3/5)))

  = 0.98

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