条件分布率 P==∑P5=,==∑P2(1-p)2 =(-1)p2(1-p)y2,(=2,3,) 当j=2,3,时,条件分布律存在 P===P{=i,=}/Pm= =p2(1-p)2/-1)p2(1-p)y2 (=1,2,…,j-1 电子科技大学4电子科技大学 条件分布率 当 j＝2, 3, …时，条件分布律存在    - = - - = = = = = = - 1 1 2 2 1 1 { } { , } (1 ) j i j j i P  j P  i  j p p ( 1) (1 ) , ( 2,3, ) = j - p 2 - p j-2 j =  P{ = i = j} = P{ = i, = j}/ P{ = j} 2 2 2 2 (1 ) /( 1) (1 ) - - = - - - j j p p j p p , ( 1,2, , 1) 1 1 = - - = i j j 