(2)简单随机抽样比估计 n=2X=RX=1.101236×826800=910502(亩) 一一一一一-一一一一一一一一一一一一■ s()≈/(1-f (S2+R22-2RS)=23095(亩) n (3)分层随机抽样简单估计 j=∑N=910780(亩) h=1 s(x)=N√v(x)=N ∑W hh h=1 =976 23%(0.475×42064.933+03043×3122571+0,2582×140.667 48975亩)(2)简单随机抽样比估计 ˆ 1.101236 826800 910502( ) R y y X RX x = = =  = 亩 2 2 2 (1 ) ˆ ( ) ( R y x f s y N S R S n −  + ˆ 2 ) 23095( ) − = RSxy 亩 (3)分层随机抽样简单估计 1 910780( ) k st h h h y N y = = =  亩 ( ) ( ) st st s y N v y = 2 1 1 1 ( ) k h h h N W S n N = = −  1 1 976 ( )(0.4375 42064.933 0.3043 31221.571 0.2582 121470.667) 23 976 = −  +  +  = 48975(亩）