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随机区组设计中删失数据的对齐秩检验AI 解读

The aligned rank test of Hodges & Lehmann (1962) is extended to censored survival data collected in matched pairs or randomized blocks. The test statistic for matched pairs is a direct extension of the original aligned rank test, whereas the test statistic for use with block size k>2 is constructed from the paired data statistics comparing all possible pairs of treatments. The efficiency of recovery of interblock information with censored matched pairs is examined by…

田间试验的线性模型、平滑与交叉验证AI 解读

Spatial methods for the analysis of agricultural field experiments are represented here as smoothing methods applied simultaneously with the estimation of treatment effects. Selection of both the form of the smoother and the degree of smoothing required may be based on cross-validation. Particular emphasis is placed in this paper on generalized least squares estimation in linear models, but the principle applies quite generally.

去趋势对格兰杰因果检验的影响AI 解读

Nonstationary time series are frequently detrended in empirical investigations by regressing the series on time or a function of time. The effects of the detrending on the tests for causal relationships in the sense of Granger are investigated using quarterly U.S. data. The causal relationships between nominal or real GNP and M1, inferred from the Granger–Sims tests, are shown to depend very much on, among other factors, whether or not series are detrended. Detrending tends…

动态回归（分布滞后）模型的识别AI 解读

Dynamic regression models (also known as distributed lag models) are widely used in engineering for quality control and in economics for forecasting. In this article I propose a procedure for specifying such models in practice. The proposed procedure requires no prewhitening and can directly handle the nonstationary series. Furthermore, the procedure cross-validates prior beliefs about causal relationships between variables with empirical findings to ensure the suitability…

用最小二乘平滑分析田间试验AI 解读

SUMMARY Assuming a smooth trend plus independent error model for the environmental effects in the yields of a field plot experiment, least squares smoothing methods are developed to estimate both the treatment effects and the unknown trend. Treatment estimates are closely related to those resulting from a generalized least squares analysis in which the covariance structure for the environmental effects has a particular form. However, the main emphases are on the accuracy of…

比较公立与私立学校：选择性偏误的令人困惑作用AI 解读

Recent articles using the same data and variants of the same estimation technique report conflicting estimates of the relative quality of education provided by public and Catholic schools. This article explains the reasons for the conflict. In so doing, the article clarifies the assumptions underlying the increasingly popular two-step methods for controlling selectivity bias and highlights the hazards of using these methods when the assumptions are not satisfied. The article…

随机区组设计中删失数据的对齐秩检验AI 解读

The aligned rank test of Hodges & Lehmann (1962) is extended to censored survival data collected in matched pairs or randomized blocks. The test statistic for matched pairs is a direct extension of the original aligned rank test, whereas the test statistic for use with block size k>2 is constructed from the paired data statistics comparing all possible pairs of treatments. The efficiency of recovery of interblock information with censored matched pairs is examined by…

田间试验的线性模型、平滑与交叉验证AI 解读

Spatial methods for the analysis of agricultural field experiments are represented here as smoothing methods applied simultaneously with the estimation of treatment effects. Selection of both the form of the smoother and the degree of smoothing required may be based on cross-validation. Particular emphasis is placed in this paper on generalized least squares estimation in linear models, but the principle applies quite generally.

与最佳者多重比较的约束同时置信区间AI 解读

For comparing $k$ treatment effects $\theta_1, \theta_2, \cdots \theta_k$, often the parameters of primary interest are $\theta_i - \max_{j\neq i}\theta_j, i = 1, \cdots, k$. In this article, we develop constrained $100P^\ast{\tt\%}$ two-sided simultaneous confidence intervals for $\theta_i - \max_{j \neq i} \theta_j$ which we refer to as (constrained) MCB intervals. It turns out that the lower bounds of the intervals imply Indifference Zone selection inference, and the…

观察性研究中的条件置换检验与倾向得分AI 解读

In observational studies, the distribution of treatment assignments is unknown, and therefore randomization tests are not generally applicable. However, permutation tests that condition on sample information about the treatment assignment mechanism can be applicable in observational studies, provided treatment assignment is strongly ignorable. These tests use the conditional distribution of the treatment assignments given a sufficient statistic for the unknown parameter of…

This paper presents results of an analysis of the labor supply response of 20-year families in the Denver Income Maintenance Experiment. The results indicate that 20-year husbands and wives do not reduce their labor supply relative to control families while 20-year single female heads of families reduce their labor supply by about the same amount as similar families on the 3and 5-year programs. The results suggest that the limited duration of the 3and 5-year experiments may…

样本选择模型与多部模型之间的选择AI 解读

Hay and Olsen (1984) incorrectly argue that a multi-part model, the two-part model used in Duan et al. (1982,1983), is nested within the sample-selection model. Their proof relies on an unmentioned restrictive assumption that cannot be satisfied. We provide a counterexample to show that the propensity to use medical care and the level of expense can be positively associated in the two-part model, contrary to their assertion. The conditional specification in the multi-part…

存在自相关时实验的最优随机化AI 解读

For a linear or spatial ordering of the experimental units, systematic methods of applying the treatments to the experimental units minimize the variance of linear contrasts of treatment means. In the linear ordering the optimal randomization scheme for the application of k treatments is to apply a treatment to every kth experimental unit, the equivalent of systematic sampling in the sampling literature. In the spatial ordering the optimal randomization schemes are…

重新定位反向回归AI 解读

I am not sure that the imperfect correlation between workers' productivity and their measured qualifications creates, as Conway and Roberts suggest, a profound dilemma for the theory of distributive justice. On the other hand, I am fairly sure that it raises issues of statistical inference. And I am quite sure that statisticians are better equipped to resolve the latter than the former. So I will consider the choice of regression for inferring salary discrimination in the…

结构的性质与发现AI 解读

Extending principles of experimentation, we discuss conditions under which nonexperimental data allow consistent estimation of effects of the kind revealed by experimentation and relevant to decisions. We show how implications of these conditions are often overlooked and how failure to distinguish between “factors” and “concomitants” makes almost anything said about a model ambiguous if not wrong. The effects to be estimated dictate the factors to be included; consistency…

观察研究从关联到因果：强可忽略处理分配检验的作用AI 解读

If treatment assignment is strongly ignorable, then adjustment for observed covariates is sufficient to produce consistent estimates of treatment effects in observational studies. A general approach to testing this critical assumption is developed and applied to a study of the effects of nuclear fallout on the risk of childhood leukemia. R.A. Fisher's advice on the interpretation of observational studies was “Make your theories elaborate”; formally, make causal theories…

论结构的本质与发现AI 解读

Extending principles of experimentation, we discuss conditions under which nonexperimental data allow consistent estimation of effects of the kind revealed by experimentation and relevant to decisions. We show how implications of these conditions are often overlooked and how failure to distinguish between “factors” and “concomitants” makes almost anything said about a model ambiguous if not wrong. The effects to be estimated dictate the factors to be included; consistency…

随机实验中非线性回归遗漏协变量导致的处理效应估计偏差AI 解读

Certain important nonlinear regression models lead to biased estimates of treatment effect, even in randomized experiments, if needed covariates are omitted. The asymptotic bias is determined both for estimates based on the method of moments and for maximum likelihood estimates. The asymptotic bias from omitting covariates is shown to be zero if the regression of the response variable on treatment and covariates is linear or exponential, and, in regular cases, this is a…

存在自相关时实验的最优随机化AI 解读

SUMMARY For a linear or spatial ordering of the experimental units, systematic methods of applying the treatments to the experimental units minimize the variance of linear contrasts of treatment means. In the linear ordering the optimal randomization scheme for the application of k treatments is to apply a treatment to every kth experimental unit, the equivalent of systematic sampling in the sampling literature. In the spatial ordering the optimal randomization schemes are…

回归与位移效应的再随机化推断：计算可行的方法AI 解读

An idea due to Quade (1973) is used to develop a method that reduces the computational load for rerandomization inferences in certain situations, and, for experiments carried out with a sufficiently small reference set of randomizations, makes computations entirely feasible. Consider an experimental design for N units for which an experimental plan E is to be chosen randomly from a set of K plans. Plan E will assign treatment dosage dE,u to unit u with postulated additive…

分布不连续与缺失个体：最低工资与失业青年AI 解读

The effects of minimum wage legislation on the employment and wage rates of youth are estimated using a new statistical approach.We find that without the minimum, not only would the percent of out-of-school youth who are employed be 4 to 6 percent higher than it is, but also that these youth would earn more.In particular, the expected hourly earnings of youth with market wage rates below the 1978 minimum are 10 percent lower with the minimum than they would be without…

考虑二分子组选择的 P 值调整AI 解读

Using a probability inequality, we show that if U = ([Udot], Ü), [Udot] = (U 1, …, U k), Ü = (U k + 1, …, U 2k ) has a multivariate normal distribution with mean vector zero and covariance matrices cov([Udot], [Udot]) = cov(Ü, Ü) = R, cov([Udot], Ü) = e'e – R, where R is a k × k correlation matrix and e = (1, …, 1), then P{|U 1| < c, …, |U 2k | < c} is minimized by setting all correlations in R equal to ½. This result is used to adjust the apparent significance of a…

工人工会身份的决定机制AI 解读

A model of the determination of the union status of workers is developed that incorporates the separate decisions of workers and potential union employers in a framework which recognizes the possibility of an excess supply of workers for existing union jobs.This theoretical framework results in an empirical problem of partial observability because information on union status is not sufficient to determine whether nonunion workers are nonunion because they do not desire union…

受限随机化设计下的显著性检验AI 解读

Experimental subjects are assigned to one of two treatments sequentially by restricted randomization assignment rules. Significance tests generated from these rules are discussed. Under rather mild conditions on the test scores the asymptotic null permutational distribution of tests based on the urn design (Wei, 1977, 1978a) is shown to be normal.