We will start with the most commonly used machine learning technique: classification. As we reviewed in the first chapter, the main idea is to automatically build a mapping between the input variables and the outcome. In the following sections, we will look at how to load the data, select features, implement a basic classifier in Weka, and evaluate its performance.
Classification
Data
For this task, we will take a look at the ZOO database. The database contains 101 data entries of animals described with 18 attributes, as shown in the following table:
| 
 animal  | 
 aquatic  | 
 fins  | 
| 
 hair  | 
 predator  | 
 legs  | 
| 
 feathers  | 
 toothed  | 
 tail  | 
| 
 eggs  | 
 backbone  | 
 domestic  | 
| 
 milk  | 
 breathes  | 
 cat size  | 
| 
 airborne  | 
 venomous  | 
 type...  |