=p"z(1-qz)(泰勒展开) Penn(n+1)n+k-1) (q=)(见P。58) k=0 p22∑ n-1 k n k-1(q2 k=0 n+k=t nn ∑C(q)"=∑C 1-」 k-n k k-1p q t=n k P(X=k=Ck-lp"q,k=n,n+1 即Xx~B(m,p)n n n p z qz − = (1− ) （泰勒展开）   = + + − = 0 ( ) ! ( 1)...( 1) k n n k qz k n n n k p z （见P。58）   = − = + − 0 1 1 ( ) k n k n k n n p z C qz    = − − −  = − − − + = = = k n n n k n k k t n n t n t n n n k t p z C qz C p q z 1 1 1 1 ( ) ( ) , , 1,... 1  = = 1 = + − − P X k C − p q k n n n n k n k 即 ~ ( , ) 1 X B n p −