Inferences on the Means of Two Log-Normal Distributions: A Computational Approach Test

In this article, we propose a novel approach for testing the equality of two log-normal populations using a computational approach test (CAT) that does not require explicit knowledge of the sampling distribution of the test statistic. Simulation studies demonstrate that the proposed approach can perform hypothesis testing with satisfying actual size even at small sample sizes. Overall, it is superior to other existing methods. Also, a CAT is proposed for testing about reliability of two log-normal populations when the means are the same. Simulations show that the actual size of this new approach is close to nominal level and better than the score test. At the end, the proposed methods are illustrated using two examples.     

论西方政治哲学的理想社会观

本文以马克思主义理想社会观对西方政治哲学的理想社会观进行了评析,认为西方政治哲学的价值理性主义和人文主义是构建理想社会的政治思维,理想社会体现了智性主义和人文主义的政治传统,理想社会建构关注财产关系的安排,制度主义是西方政治哲学理想社会的生长点.     

谈分级显性意义假说对反语中的认知参照点的解释力

本文运用Giora的分级显性意义假说分析了Langacker的认知参照点理论，并对反语中的认知参照点进行分析，得出反语中的认知参照点也是层级突显的结论，为反语的理解提供一个新的视角。     

A modified false discovery rate multiple-comparisons procedure for discrete data, applied to human immunodeficiency virus genetics

Summary.  To help to design vaccines for acquired immune deficiency syndrome that protect broadly against many genetic variants of the human immunodeficiency virus, the mutation rates at 118 positions in HIV amino-acid sequences of subtype C versus those of subtype B were compared. The false discovery rate (FDR) multiple-comparisons procedure can be used to determine statistical significance. When the test statistics have discrete distributions, the FDR procedure can be made more powerful by a simple modification. The paper develops a modified FDR procedure for discrete data and applies it to the human immunodeficiency virus data. The new procedure detects 15 positions with significantly different mutation rates compared with 11 that are detected by the original FDR method. Simulations delineate conditions under which the modified FDR procedure confers large gains in power over the original technique. In general FDR adjustment methods can be improved for discrete data by incorporating the modification proposed.     

Hypothesis Testing in a Rayleigh Diffusion Model

Applying the large and moderate deviations for the log-likelihood ratio of the Rayleigh diffusion model, we give the negative regions in testing Rayleigh diffusion model and obtain the decay rates of the error probabilities.     

The missing women in STEM? Assessing gender differentials in the factors associated with transition to first jobs

Women remain underrepresented in the STEM workforce. We assess explanations for women's underrepresentation in STEM jobs, focusing on a cohort that came of age in the 1980s and 1990s, when women dramatically increased their representation in the scientific labor force. Data are from the NLSY79, and our analysis focuses on members of this cohort who received a college degree, with an emphasis on those who completed a degree in a STEM field. Our analyses test the extent to which college major, expectations to work in STEM, and family expectations shaped transitions into STEM occupations within two years of degree completion. Among those majoring in STEM fields there were no gender differences in transitioning into STEM jobs, though there were sizable differences in transitions to STEM employment by field of study. Of note are gender differences in associations between family expectations and transitions into STEM employment. The most career oriented women, who expected to marry late and limit fertility, were no more likely to enter STEM jobs than were women who anticipated marrying young and having two or more children. The men most likely to enter STEM occupations, in contrast, adhered to significantly more conventional gender ideologies than their female counterparts, expecting to marry at younger ages but also to remain childless. Results of our regression decomposition indicated that marriage and family expectations and gender ideology worked in opposite directions for men and women. Nonetheless, the majority of the gender disparity in transitions into STEM jobs was related to women's underrepresentation in engineering and computer science fields of study.     

Testing the Granger Noncausality Hypothesis in Stationary Nonlinear Models of Unknown Functional Form

In this article, we propose a general method for testing the Granger noncausality hypothesis in stationary nonlinear models of unknown functional form. These tests are based on a Taylor expansion of the nonlinear model around a given point in the sample space. We study the performance of our tests by a Monte Carlo experiment and compare these to the most widely used linear test. Our tests appear to be well-sized and have reasonably good power properties.     

Issues in Second Language Acquisition

Input plays an important part in the acquisition of second language.This report will just focus on Krashen＇s Input Hypothesis and Long＇s Interaction Hypothesis concerning input.First a summary will be made about the two theories,and then the writer will make a comparison between the two.This report will conclude with the writer＇s observations of how her thinking about ＇input＇ has been clarified in the process of preparing and writing this report.     

Testing Hypotheses in Nonparametric Models of Production

Data envelopment analysis (DEA) and free disposal hull (FDH) estimators are widely used to estimate efficiency of production. Practitioners use DEA estimators far more frequently than FDH estimators, implicitly assuming that production sets are convex. Moreover, use of the constant returns to scale (CRS) version of the DEA estimator requires an assumption of CRS. Although bootstrap methods have been developed for making inference about the efficiencies of individual units, until now no methods exist for making consistent inference about differences in mean efficiency across groups of producers or for testing hypotheses about model structure such as returns to scale or convexity of the production set. We use central limit theorem results from our previous work to develop additional theoretical results permitting consistent tests of model structure and provide Monte Carlo evidence on the performance of the tests in terms of size and power. In addition, the variable returns to scale version of the DEA estimator is proved to attain the faster convergence rate of the CRS-DEA estimator under CRS. Using a sample of U.S. commercial banks, we test and reject convexity of the production set, calling into question results from numerous banking studies that have imposed convexity assumptions. Supplementary materials for this article are available online.