Second Order stochastic Dominance MWG Definition 6 D 2: For any two distributions F( and G( with the same mean, F( second order stochastically dominates(or is less risky than)G( if for every nondecreasing concave function R+→ R we have ∫(x)dH(x)≥J(x)dG(x) Other definition: the variable y is a mean preserving spread of x, if y=X+z where ∫zdH(=)=0Second Order Stochastic Dominance MWG Definition 6.D.2: For any two distributions F(.) and G(.) with the same mean, F(.) second order stochastically dominates (or is less risky than) G(.) if for every nondecreasing concave function u :    we have  uxdFx   uxdGx Other definition: the variable y is a mean preserving spread of x, if yxz where zdHz  0