Ex. 17.2 Ex. 17.2 Consider random variables X1,X2,X3,X4. In each of the following cases draw a graph that has the given independence relations: (a) X1⊥X3|X2 and X2⊥X4|X3. (b) X1⊥X4|X2,X3 and X2⊥X4|X1,X3. (c) X1⊥X4|X2,X3,X1⊥X3|X2,X4 and X3⊥X4|X1,X2. Soln. 17.2 (a) (b) (c)