In this example, all variables are boolean The training set consists of the following examples: x1 x2 x3 f 1 0 0 0 0 1 1 0 1 0 1 1 The learning model consists of {AND, OR, XOR, NAND, NOR, x1 /\ x3} There error for each model is 1/3, 2/3, 2/3,2/3, 1/3, 0/3. So x1 /\ x3 is the best. The actual target function was XOR(x2,x3). The real error in this choice was 4/8. The real error for the example 1 choice was 5/8. The real error for OR is only 3/8.