Values(Wind) = {Weak, Strong}
S = {D4, D5, D6, D10, D14}
S = [3+, 2—]	S_Weak = [3+, 0—]		S_Strong = [0+, 2—]

Entropy(S) = Entropy[3+, 2—]
= — (2/5).log2 (2/5) — (3/5).log2 (3/5) = 0.970

Similarly,
Entropy(S_Weak) = Entropy[3+, 0—] = 0
Entropy(S_Strong) = Entropy[0+, 2—] = 0

Information Gain(S, Wind) = Entropy(S) — (3/5).Entropy(S_Weak) — (2/5).Entropy(S_Strong)
= 0.970 — 0 - 0
= 0.970