A shaman is attacking a dragon the shamans normal attack does 250 damage there is 15% chance of getting a critical strike for 500 damage and a 20% chance of getting a windfury attack for 800 damage there is also a 10% chance that his attack will miss causing 0 damage let the random variable x represent the damage his attack does

which would be more useful a talent that increases the shaman overall damage by 5% or a a talent that increases the chance of getting a critical strike by 5%

a.overall damage

b. critical strike

c. equally useful