Swim preference – representing data using a decision tree

We may have certain preferences that determine whether or not we would swim. These can be recorded in a table, as follows:

Swimming suit	Water temperature	Swim preference
None	Cold	No
None	Warm	No
Small	Cold	No
Small	Warm	No
Good	Cold	No
Good	Warm	Yes

 

The data in this table can alternatively be presented in the following decision tree:

Figure 3.1: Decision tree for the Swim preference example

At the root node, we ask the question—do you have a swimming suit? The response to the question separates the available data into three groups, each with two rows. If the attribute is swimming suit = none, then two rows have the swim preference attribute as no. Therefore, there is no need to ask a question about the temperature of the water...