考虑方差分量(混合线性)模型y=Xβ+U1ξ1+U2ξ2+…+Ukξk,这里Xn×p,Ui,n×ti为已知设计矩阵,βp×1是固定效应,ξi是ti×1随机效应向量,满足E(ξi)=0,cov(ξi)=σi^2Ⅰti,ξi都不相关.往往Uk=Ⅰn,ξk=ek,即最后一项为随机误差,β∈R^p和σi^2〉0(i=1,2,…,k)为未知参数.我们考虑β的可估函数Sβ,选取二次损失函数L(d,Sβ)=(d-Sβ)'(d-Sβ)/∑i=1^k ciσi^2+β'X'Vk^-1Xβ,然后在线性估计类中给出Sβ的惟一的minimax估计.
Consider the mixed linear model y=Xβ+U1ξ1+U2ξ3+…+Ukξk,E(ξi)=0,cov(ξi,ξj)=0,i≠j,cov(ξi,ξj)=σi^2Vi,i,j=1,2,…,k, vector, where y is a random n ×1 column n×1 column vector,Xn×p,Ui,n×ti,and Vi≥0 are known.β∈R^p,σi^2〉0 are parmeters ,i=1,2,…,k.Choose a loss function L(d,Sβ)=(d-Sβ)'(d-Sβ)/∑i=1^k ciσi^2+β'X'Vk^-1XB We obtain the unipue minimax estimator of linear estimable functions Sβin the class of linear estimatiors.