Comparison of ANOVA-F and ANOM tests with regard to type I error rate and test power

A Monte Carlo simulation was conducted to compare the type I error rate and test power of the analysis of means (ANOM) test to the one-way analysis of variance F-test (ANOVA-F). Simulation results showed that as long as the homogeneity of the variance assumption was satisfied, regardless of the shape of the distribution, number of group and the combination of observations, both ANOVA-F and ANOM test have displayed similar type I error rates. However, both tests have been negatively affected from the heterogeneity of the variances. This case became more obvious when the variance ratios increased. The test power values of both tests changed with respect to the effect size (Δ), variance ratio and sample size combinations. As long as the variances are homogeneous, ANOVA-F and ANOM test have similar powers except unbalanced cases. Under unbalanced conditions, the ANOVA-F was observed to be powerful than the ANOM-test. On the other hand, an increase in total number of observations caused the power values of ANOVA-F and ANOM test approach to each other. The relations between effect size (Δ) and the variance ratios affected the test power, especially when the sample sizes are not equal. As ANOVA-F has become to be superior in some of the experimental conditions being considered, ANOM is superior in the others. However, generally, when the populations with large mean have larger variances as well, ANOM test has been seen to be superior. On the other hand, when the populations with large mean have small variances, generally, ANOVA-F has observed to be superior. The situation became clearer when the number of the groups is 4 or 5.     

On constructing T 2 control charts for retrospective examination

In this paper we consider the issue of constructing retrospective T ² control chart limits so as to control the overall probability of a false alarm at a specified value. We describe an exact method for constructing the control limits for retrospective examination. We then consider Bonferroni-adjustments to Alt's control limit and to the standard x ² control limit as alternatives to the exact limit since it is computationally cumbersome to find the exact limit. We present the results of some simulation experiments that are carried out to compare the performance of these control limits. The results indicate that the Bonferroni-adjusted Alt's control limit performs better that the Bonferroni-adjusted x ² control limit. Furthermore, it appears that the Bonferroni-adjusted Alt's control limit is more than adequate for controlling the overall false alarm probability at a specified value.     

Testing the Equality of the Noncentrality Parameters of Two Noncentral t-Distributions with Identical Degrees of Freedom

The problem of testing the equality of the noncentrality parameters of two noncentral t-distributions with identical degrees of freedom is considered, which arises from the comparison of two signal-to-noise ratios for simple linear regression models. A test procedure is derived that is guaranteed to maintain Type I error while having only minimal amounts of conservativeness, and comparisons are made with several other approaches to this problem based on variance stabilizing transformations. The new procedure derived in this article is shown to have good properties and will be useful for practitioners.     

A more powerful unconditional exact test of homogeneity for 2 × c contingency table analysis

The classical unconditional exact p-value test can be used to compare two multinomial distributions with small samples. This general hypothesis requires parameter estimation under the null which makes the test severely conservative. Similar property has been observed for Fisher's exact test with Barnard and Boschloo providing distinct adjustments that produce more powerful testing approaches. In this study, we develop a novel adjustment for the conservativeness of the unconditional multinomial exact p-value test that produces nominal type I error rate and increased power in comparison to all alternative approaches. We used a large simulation study to empirically estimate the 5th percentiles of the distributions of the p-values of the exact test over a range of scenarios and implemented a regression model to predict the values for two-sample multinomial settings. Our results show that the new test is uniformly more powerful than Fisher's, Barnard's, and Boschloo's tests with gains in power as large as several hundred percent in certain scenarios. Lastly, we provide a real-life data example where the unadjusted unconditional exact test wrongly fails to reject the null hypothesis and the corrected unconditional exact test rejects the null appropriately.     

"毛主义"话语的起源、性质与内涵--简评史华慈《中国的共产主义运动与毛泽东的崛起》

美国哈佛大学已故教授史华慈是当代最著名的现代中国问题研究专家,其名著<中国的共产主义运动与毛泽东的崛起>是其博士论文并是其成名作.该书中,史华慈首次提出"毛主义"的学术范式,对其形成、内涵和意义进行了最早的论证.他强调"毛主义"在革命的理念上与斯大林主义有着明显的差异,毛主义是"由农民所进行的革命",而不仅仅是"为了农民而进行的革命".前者强调农民自身就是革命的主体、性质和动力,而后者则只把农民利益当作革命的重要目标之一.显然二者的意义有着本质的不同.史华慈的这些论点对西方毛泽东研究领域影响极大,并引起了广泛争论.     

广东电子信息产业战略发展重点的若干探究

本文通过对广东省电子信息产业现状的研究及对国内电子产品市场需求的预测,提出了应重点发展投资类和元器件类电子产品及实现战略目标应采取的措施。     

Prediction of Times to Failure of Censored Items for a Simple Step-Stress Model with Regular and Progressive Type I Censoring from the Exponential Distribution

The problem of predicting times to failure of units from the Exponential Distribution which are censored under a simple step-stress model is considered in this article. We discuss two types of censoring—regular and progressive Type I—and two kinds of predictors—the maximum likelihood predictors (MLP) and the conditional median predictors (CMP) for each type of censoring. Numerical examples are used to illustrate the prediction methods. Using simulation studies, mean squared prediction error (MSPE) and prediction intervals are generated for these examples. MLP and the CMP are then compared with respect to MSPE and the prediction interval.     

基于FPGA的高频等精度频率计设计与实现

文章介绍了等精度频率计误差分析和实现原理,在Altera新一代FPGA/PLD开发软件QuartusⅡ 中运用硬件描述语言Verilog HDL编程,通过单片机控制EP1 C12Q240I7芯片实现等精度频率计的设计,频率计可通过分频测量800 MHZ～1 400 MHZ之间的高频信号频率,大大提高了测量精度,实验证明测量精度为0.000 03％以下.     

严复视界中的《周易》

严复具有自觉的哲学意识,他所认定的中国哲学的经典是《周易》、《老子》、《庄子》。严复十分重视《周易》,尽管没有像对待《老子》、《庄子》那样进行点评,他对《周易》的诠释围绕着哲学思想展开,在一定程度上扭转了前人以宗教言《周易》的局面;严复对《周易》的解读是其国学研究的重要组成部分,并且富有开创性。     

英语话语标记语之构式语法分析——以“Imean”为例

话语标记语“Imean”有多种语用功能意义。在构式语法的框架下,试图把“Imean”作为一个构式来研究,分析其形式、意义、功能,然后在此基础上提出“Imean”的形成是一个语法化的结果这样一个假设,是从第一人称的动补构式[verb＋complement]语法化为话语标记语构式[discoursemarker]。构式语法可以成功解释语法化的诱因。这样的分析可促进运用构式语法对话语标记语的研究,同时也显示出构式语法的强大解释力。