Ry=io hy -ya个n [1+(n-1)r] 当家系足够大时： Ryia 2008-5-27 102008-5-27 10 ⎥⎥⎦⎤ ⎢⎢⎣⎡ −+ −+ =⋅ −+ −+ ⋅⋅ −+ = = ])1(1[ )1(1 ])1(1[ ])1(1[)1(1 2 2 2 rnn rn hih rn rn n n i hiR A P A P fff σ σ σ R ih r r f P A = σ 2 当家系足够大时：