28 Computing information gain Information gain: information before splitting – information after splitting Information gain for attributes from weather data: gain(Outlook ) = 0.247 bits gain(Temperature ) = 0.029 bits gain(Humidity ) = 0.152 bits gain(Windy ) = 0.048 bits gain(Outlook )= info([9,5]) – info([2,3],[4,0],[3,2])‏ = 0.940 – 0.693 = 0.247 bits