考虑回归模型: yi=xiβ+g(ti)+σiei,i=1,2,…,n,其中σi=f(ui),(xi,ti,ui)是固定非随机设计点列, f(·),g(·)是未知函数,β是待估参数,ei是随机误差且关于非降σ-代数列{Fi,i≥1}为鞅差序列.对文献[1]给出的基于f(·)及g(·)的一类非参数估计的β的最小二乘估计β^-n和加权最小二乘估计β^-n,在适当条件下证明了它们的强相合性,推广了文献[6]在ei为iid情形下的结果.
Consider the heteroscedastic: regression model: yi = xiβ+g(ti)+σiei,j= 1,2,…, n, whereσi = f(ui). Here the design points (xi,ti,ui) are known and nonrandom, g and f are unknown functions , andβis the parameter needed to be estimated, e i is the random error and a martingale difference sequence in relation to the undecreasingσ-algebra series {Fi, i.≥1}. For the least squares estimatorβ^-nand the weighted least squares estimatorβ^-nofβgiven in [1] based on the family of nonparametric estimates of y(·) and f(·), the authors establish their strong consistency under suitable conditions, thereby improve the the result where ei is iid in [6].