For certain point and interval estimation problems, sequential procedures are proposed for choosing an estimator (from the class of trimmed means with trimming proportion in a specified range) as well as a sample size on which to base the estimator. It is shown that these procedures, which do not require knowledge of the best trimming proportion or the asymptotic variance of the corresponding trimmed mean, are asymptotically efficient with respect to the procedure that uses…
In the sequential design of experiments an experimenter performs experiments sequentially to make an eventual inference about the true state of nature. A Bayesian formulation of this problem is considered. The parameter space is assumed finite and there are a finite number of repeatable experiments. Sufficient conditions are given for a procedure to be second order efficient as the sampling costs approach zero. The asymptotic analysis of a related Markov control problem is…
The errors-in-variables model in which the unobserved true values satisfy multiple linear restrictions is considered. Under the assumptions that the unobservable true values are normally distributed and that an estimator of the covariance matrix of the measurement error is available, the maximum likelihood estimators are derived. The limiting properties of the estimators are obtained for a wide range of assumptions, including the assumption of fixed true values.
This paper is about the asymptotic distribution of linear combinations of stratum means in stratified sampling, with and without replacement. Both the number of strata and their size is arbitrary. Lindeberg conditions are shown to guarantee asymptotic normality and consistency of variance estimators. The same conditions also guarantee the validity of the bootstrap approximation for the distribution of the $t$-statistic. Via a bound on the Mallows distance, situations will be…
Consider a sample from a normal population with mean, $\mu$, and variance unknown. Suppose it is desired to test $H_0:\mu \leq \mu_0$ versus $H_1:\mu \geq \mu_1$, with the region $H^I_1:\mu_0 < \mu < \mu_1$ being a (nonempty) indifference zone. It is shown that the usual Student's $t$-test is inadmissible for this problem. An alternative test is proposed. The two sided problem with indifference region is also discussed. By contrast with the above result, the usual Student's $t$…
A theory is developed following work by Williams (1952) and Kiefer (1960) for exact treatment designs in one dimension in which the errors are a stationary process. It is shown that the designs which achieve the minimax value of any of a wide class of functionals on the information matrix for estimation of treatment differences have a special property. If the process is autoregressive of order $p$ then a random piece of the design of length $p + 1$ exhibits uncorrelated…
This article is a survey of Jack Kiefer's published works in areas other than design of experiments. The approximately 50 articles can be divided into categories by subject matter. These categories will be discussed individually in the following review. At times Jack worked in several areas simultaneously and ideas from one area sometimes influenced work in another. Some of these influences are noted in the following survey, as the categories are discussed in roughly the…
This note is concerned with how to replace assessment of a "true" prior on a nonparametric family of distributions--which is usually infeasible--by assessment of an approximating prior with support in a parametrized subfamily, in such a way that the posterior derived from the parametric model is close to the "true" posterior. In general it is not sufficient that the approximating prior be close to the true prior in the sense of weak convergence, and we characterize the…
Buckley and James (1979) proposed an estimation method for linear regression models with unspecified residual distribution and right-censored response variables. In this paper we consider weak consistency of the regression parameter estimators under regularity conditions which avoid restrictions on the censoring patterns.
We derive invariance principles for processes associated with symmetric statistics of arbitrary order. Using a Poisson sample size, such processes can be viewed as functionals of a Poisson Point Process. Properly normalized, these functionals converge in distribution to functionals of a Gaussian random measure associated with the distribution of the observations. We thus obtain a natural description of the limiting process in terms of multiple Wiener integrals. The results…
Three approaches to a nonparametric maximum likelihood problem are considered. One, based on the method of "sieves", is shown to include the other two. The sieve considered is a double exponential convolution sieve. A closed form solution is given for certain values of the sieve parameter.
In the theory of competing risks, the nonparametric Kaplan-Meier estimator plays an important role. In this paper, a bivariate nonparametric estimator for the competing risk problem is given, which for the special case of independent causes gives the Kaplan-Meier estimator. This paper also introduces a matrix $w$, through which dependent models for the competing problem can be studied. These results also indicate the special case on the matrix $w$ for which the bounds to the…
Czeslaw Stepniak · Song-Gui Wang · C. F. Jeff Wu·刊期 1984-03-01 · 卷 12(1)·The Annals of Statistics已编入正刊
已知协方差下线性试验的比较AI 解读
For two linear experiments $d_1 = L(X_1\beta, V_1)$ and $d_2 = L(X_2\beta, V_2)$ where the covariances $V_1$ and $V_2$ are known and can be singular or nonsingular, we characterize the following relations: $d_1$ at least as good as $d_2, d_1$ better than $d_2$, and $d_1$ equivalent to $d_2$. Sometimes only a subset of parameters is of interest to the experimenter. We extend the above relations between $d_1$ and $d_2$ to estimation of a common subset of parameters and give…
Simultaneous estimation of $p(p \geq 3)$ location parameters are considered under quadratic loss. Explicit estimators which dominate the best invariant one are given mainly when coordinates of the best invariant one are independently, identically and symmetrically distributed. Effectiveness of integration by parts in evaluating the risk function of the dominating estimator is shown for three typical continuous distributions (uniform, double exponential and $t$). Further…
In the location estimation problem, translation equivariant estimators are considered. It is shown that under a mild regularity condition the distribution of such estimators is more spread out than a particular distribution which is defined in terms of the sample size and the density of the i.i.d. observations. Some consequences of this so-called spread-inequality are discussed, namely the Cramer-Rao inequality, an asymptotic minimax inequality and the efficiency of the…
Let $\mathbf{X}_1, \mathbf{X}_2,\cdots$ be independent $p$-variate normal vectors with $E \mathbf{X}_\alpha \equiv \beta \mathbf{Y}_\alpha, \alpha = 1,2,\cdots$ and same p.d. dispersion matrix $\Sigma$. Here $\beta: p \times q$ and $\Sigma$ are unknown parameters and $\mathbf{Y}_\alpha$'s are known $q \times 1$ vectors. Writing $\beta = (\beta'_1 \beta'_2)' = (\beta_{(1)}\beta_{(2)})$ with $\beta_i: p_i \times q(p_1 + p_2 = p)$ and $\beta_{(i)}: p \times q_i(q_1 + q_2 = q)$,…
Optimal Bayesian experimental designs for estimation and prediction in linear models are discussed. The designs are optimal for estimating a linear combination of the regression parameters $\mathbf{c}^T\theta$ or prediction at a point where the expected response is $\mathbf{c}^T\mathbf{\theta}$ under squared error loss. A distribution on $\mathbf{c}$ is introduced to represent the interest in particular linear combinations of the parameters. In the usual notation for linear…
We consider the nearly linear regression problem when the assumed first degree model is contaminated by some small constant, and the design space consists of finitely many points, symmetrically distributed on the interval $\lbrack -1/2, 1/2\rbrack$. Under the usual squared loss function for the estimation of the slope and the intercept, and with the use of the least squares estimators, the problem is to find the designs which are optimal in the sense of minimizing the…
In this paper the asymptotic relative deficiency of the sample $q$-quantile with respect to kernel type estimators of the $q$-quantile is evaluated. The comparison is based on the mean square errors of the estimators. The result suggests a purely analytic measure of performance within the class of kernels. It is notable that a similar situation occurs when kernel estimators of a distribution function are studied.
Weak laws of large numbers and central limit theorems are proved for integrated square error of kernel estimators of regression functions. The regressor is assumed to take values in $\mathbb{R}^p$, and the regressand, $X$, to be real valued. It is shown that in many cases, integrated square error is asymptotically normally distributed and independent of the $X$-sample. As an application, a test for the regression function (such as that proposed by Konakov) is seen to be…
Under suitable conditions, we show that the cross-validated nearest neighbor estimates for the unknown smooth regression function in $R^p$ is asymptotically consistent.
Theo Gasser · Hans-Georg Muller · Walter Kohler · Luciano Molinari · Andrea Prader·刊期 1984-03-01 · 卷 12(1)·The Annals of Statistics已编入正刊
生长曲线的非参数回归分析AI 解读
In recent years, nonparametric curve estimates have been extensively explored in theoretical work. There has, however, been a certain lack of convincing applications, in particular involving comparisons with parametric techniques. The present investigation deals with the analysis of human height growth, where longitudinal measurements were collected for a sample of boys and a sample of girls. Evidence is presented that kernel estimates of acceleration and velocity of height,…
This paper is about the asymptotic distribution of linear combinations of stratum means in stratified sampling, with and without replacement. Both the number of strata and their size is arbitrary. Lindeberg conditions are shown to guarantee asymptotic normality and consistency of variance estimators. The same conditions also guarantee the validity of the bootstrap approximation for the distribution of the t-statistic. Via a bound on the Mallows distance, situations will be…
An Alternative to Student's t-Test for Problems with Indifference Zones
Consider a sample from a normal population with mean, μ, and variance unknown. Suppose it is desired to test H0:μ≤μ0 versus H1:μ≥μ1, with the region H1I:μ0<μ<μ1 being a (nonempty) indifference zone. It is shown that the usual Student's t-test is inadmissible for this problem. An alternative test is proposed. The two sided problem with indifference region is also discussed. By contrast with the above result, the usual Student's t…
A theory is developed following work by Williams (1952) and Kiefer (1960) for exact treatment designs in one dimension in which the errors are a stationary process. It is shown that the designs which achieve the minimax value of any of a wide class of functionals on the information matrix for estimation of treatment differences have a special property. If the process is autoregressive of order p then a random piece of the design of length p+1 exhibits uncorrelated…
In the theory of competing risks, the nonparametric Kaplan-Meier estimator plays an important role. In this paper, a bivariate nonparametric estimator for the competing risk problem is given, which for the special case of independent causes gives the Kaplan-Meier estimator. This paper also introduces a matrix w, through which dependent models for the competing problem can be studied. These results also indicate the special case on the matrix w for which the bounds to the…
For two linear experiments d1=L(X1β,V1) and d2=L(X2β,V2) where the covariances V1 and V2 are known and can be singular or nonsingular, we characterize the following relations: d1 at least as good as d2,d1 better than d2, and d1 equivalent to d2. Sometimes only a subset of parameters is of interest to the experimenter. We extend the above relations between d1 and d2 to estimation of a common subset of parameters and give…
Simultaneous estimation of p(p≥3) location parameters are considered under quadratic loss. Explicit estimators which dominate the best invariant one are given mainly when coordinates of the best invariant one are independently, identically and symmetrically distributed. Effectiveness of integration by parts in evaluating the risk function of the dominating estimator is shown for three typical continuous distributions (uniform, double exponential and t). Further…
Let X1,X2,⋯ be independent p-variate normal vectors with EXα≡βYα,α=1,2,⋯ and same p.d. dispersion matrix Σ. Here β:p×q and Σ are unknown parameters and Yα's are known q×1 vectors. Writing β=(β1′β2′)′=(β(1)β(2)) with βi:pi×q(p1+p2=p) and β(i):p×qi(q1+q2=q),…
Optimal Bayesian experimental designs for estimation and prediction in linear models are discussed. The designs are optimal for estimating a linear combination of the regression parameters cTθ or prediction at a point where the expected response is cTθ under squared error loss. A distribution on c is introduced to represent the interest in particular linear combinations of the parameters. In the usual notation for linear…
We consider the nearly linear regression problem when the assumed first degree model is contaminated by some small constant, and the design space consists of finitely many points, symmetrically distributed on the interval [−1/2,1/2]. Under the usual squared loss function for the estimation of the slope and the intercept, and with the use of the least squares estimators, the problem is to find the designs which are optimal in the sense of minimizing the…
In this paper the asymptotic relative deficiency of the sample q-quantile with respect to kernel type estimators of the q-quantile is evaluated. The comparison is based on the mean square errors of the estimators. The result suggests a purely analytic measure of performance within the class of kernels. It is notable that a similar situation occurs when kernel estimators of a distribution function are studied.
Weak laws of large numbers and central limit theorems are proved for integrated square error of kernel estimators of regression functions. The regressor is assumed to take values in Rp, and the regressand, X, to be real valued. It is shown that in many cases, integrated square error is asymptotically normally distributed and independent of the X-sample. As an application, a test for the regression function (such as that proposed by Konakov) is seen to be…
Under suitable conditions, we show that the cross-validated nearest neighbor estimates for the unknown smooth regression function in Rp is asymptotically consistent.