Let Y 1 ,Y 2 ,Y 3 ,Y 4 be the order tatitic of a U(0,θ) random ample X 1 ,X 2 ,X 3 ,X 4 . (a) Find the joint pdf of (V 1 ,V 2 ,V 3 ) , where V 1 = Y 2 Y 1 ,V 2 = Y 3 Y 2 , and V 3 = Y 4 Y 3 . (b) Find the marginal pdf of V 2