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双变量均含测量误差时的稳健直线估计AI 解读

The estimator holding the central place in the theory of the multivariate “errors-in-the-variables” (EV) model results from performing orthogonal regression on variables rescaled according to the covariance matrix of the errors. Our simulations on the univariate model essentially relegate this estimator to use only in large samples on data with no trace of outlier contamination. A modification requiring a robust preliminary slope is proposed that essentially sets out the…

季节调整的图形方法AI 解读

Graphical displays deserve to be a routine part of seasonal adjustment, and their routine use is now feasible because of the current revolution in computer graphical hardware and software. We present and illustrate seven graphical displays that provide powerful tools for judging the adequacy of the seasonal adjustment of a series and for understanding the behavior of the trend, seasonal, and irregular components.

检验分布差异的四分位数检验AI 解读

We propose a simple nonparametric statistic using sample quartiles to test differences in distribution. Simulation results suggest that the test is about equal in power over a wide range of alternatives to the familiar procedure of Kolmogorov and Smirnov. When the two distributions compared differ in both location and dispersion, the quartile test may be more sensitive than the Kolmogorov-Smirnov, Wilcoxon rank-sum, Siegel-Tukey, and runs tests.

von Neumann 随机性比率检验的秩版本AI 解读

Although rank tests for randomness were proposed in the literature as early as 1943, no such test has gained wide acceptance comparable to, say, Spearman's rho test. This may be due to the lack of small-sample theory and of tables of critical values to enable such a test to be carried out on small samples. In this article, we consider the rank version of the von Neumann ratio statistic and we obtain the critical values of this statistic under the randomization hypothesis. In…

时间序列变量间预测关系检验：蒙特卡洛研究AI 解读

Bivariate time series models have been used extensively to analyze the relationship between pairs of economic variables. Various tests have been proposed that can be used to examine the adequacy of specific models. The empirical literature is noteworthy for the frequency with which different authors using different tests reach different conclusions, and for the apparent lack of evidence for certain relationships strongly suggested by economic theory. The objective of this…

加速寿命试验中的分布假设检验AI 解读

In this paper we consider the problem of inference from accelerated life tests in which a common parametric family of life distributions at the different stress levels is not specified in advance. By assuming a time transformation function, which is a version of the familiar inverse power law, we give a procedure for testing hypotheses that the unknown distributions are specified members of a location-scale family. The behavior of the test procedure is indicated by some…

混合样本的参数估计AI 解读

Assume that a sample is a mixture of two samples from two different populations with distributions Fθ1 and Fθ2 . Given the form of Fθ , estimators of θ1 and θ2 are introduced. It is shown that the estimators are consistent and their asymptotic joint distribution is derived. The suggested estimators are compared with the maximum likelihood estimators and the method of moments estimators. For small sample sizes the comparison is done by a Monte Carlo study. For large sample…

广义 F 分布的卷积AI 解读

The generalized F variate is the ratio of two independent gamma variates, and its distribution includes as special cases such distributions as the inverted beta, Lomax, and Snedecor's F, Based on convolution, the distribution function of the sum of two independent generalized F variates is derived in terms of a Lauricella-Saran hyper-geometric function of three variables. The results are applied, with numerical examples given, to (a) a Bayesian analysis of the availability…

正态均值比的同时置信区间AI 解读

Given one or more groups of multivariate normal samples, methods are presented for forming simultaneous confidence intervals of all ratios of linear forms of the mean vectors. The methods cover the cases of equal or unequal covariances. In a simultaneous inference context, they are multivariate extensions of a method due to Fieller (1954) for estimation of the ratio of two normal means.

Sichel 复合泊松分布的推断AI 解读

In a long-tailed compound Poisson distribution introduced by Sichel, the probabilities can only readily be calculated if one of the parameters λ has half-integer values, that is, λ = m + 1/2, m integer. The maximum likelihood estimation of this parameter is compared with an approximate method derived from a grid of half-integer values. It is found that the approximate method, which avoids excessive special computation, yields inferences indistinguishable from those based on…

Kaplan–Meier 估计量的小样本结果AI 解读

Whereas much is known about the asymptotic properties of the Kaplan-Meier (1958) estimator (KME) of a survival function, exact results for small samples have been difficult to obtain. In this article, we obtain an exact expression for the αth moment (α > 0) of the KME under a model of proportional hazards. This enables us, under proportional hazards, to (a) study the bias of the KME, and (b) compare the exact variance of the KME to its asymptotic variance.

混合寿命试验中指数分布参数的置信区间AI 解读

In life testing, type I and type II censoring may be combined to form a hybrid life test. Epstein (1954) introduced this testing scheme and Epstein (1960b) proposed a two-sided confidence interval to estimate the mean lifetime, 8, of an exponential lifetime following such a test. His conjecture is modified slightly and a proof is given that establishes the validity of the proposed confidence interval.

额外序列依赖下 Durbin–Watson 检验与 WLS 估计的表现AI 解读

Monte Carlo simulation is used to study the power of the Durbin-Watson test and the properties of the corresponding weighted least squares (WLS) estimates when there is serial correlation in the disturbance term, in addition to first-order autocorrelation. The results indicate that the Durbin-Watson test detects first-order autocorrelation, even when other forms of serial dependence are also present. However, routine use of WLS estimation when the Durbin-Watson test is…

存在无应答时利用辅助信息的有限总体总量贝叶斯估计AI 解读

This article presents a Bayesian approach to estimation, in a sample survey setting, of a finite population total for some characteristic of interest when nonresponse is present. A general model is described for situations where a Hansen-Hurwitz sampling plan is used. The model makes use of concomitant information that is related both to the characteristic of interest and to the probability of response. A simple example is included to illustrate the usefulness of the…

基于 ARIMA 模型的季节调整方法AI 解读

This article proposes a model-based procedure to decompose a time series uniquely into mutually independent additive seasonal, trend, and irregular noise components. The series is assumed to follow the Gaussian ARIMA model. Properties of the procedure are discussed and an actual example is given.

股票收益风险结构变化的贝叶斯稳健检测AI 解读

In this article we provide a statistical procedure for the analysis of stock market prices that is robust toward departures from the normal distribution assumption and that can detect and evaluate a shift of parameters at an unknown time point. The method is an adaptation of a Bayesian inferential procedure developed by Box and Tiao that allows data to deviate moderately from the normal distribution model. It is applied to a set of U.S. stock market prices for 1971–1974. In…

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混合样本中的参数估计AI 解读

Assume that a sample is a mixture of two samples from two different populations with distributions Fθ1 and Fθ2 . Given the form of Fθ , estimators of θ1 and θ2 are introduced. It is shown that the estimators are consistent and their asymptotic joint distribution is derived. The suggested estimators are compared with the maximum likelihood estimators and the method of moments estimators. For small sample sizes the comparison is done by a Monte Carlo study. For large sample…

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单样本位置问题的二元非参数检验AI 解读

Many nonparametric competitors to Hotelling's T2 test lack T 2's property of invariance under linear transformations. Such tests have power and efficiency that depend on the direction of shift and the covariance matrix of the alternative distribution. This article modifies a previously proposed bivariate sign test and signed rank test to overcome this difficulty. Asymptotic results and a Monte Carlo study indicate that the efficiency and small-sample power of the new…