基于多重抽样框的连续性抽样估计方法研究

多重抽样框可以解决单一抽样框难以完整覆盖流动性目标总体的难题,连续性抽样调查则可以获取变量的时序观测数据,对总体现象进行追踪调查。本文将多重抽样框调查与连续性抽样调查两种方法结合在一起进行研究,深入分析基于多重抽样框的连续性抽样估计方法。文章首先设计了连续性调查环境下总体结构变动表;然后,在简单随机抽样假定下的轮换样本调查情形开展研究,设计了14种参数缩减方法对构建的似然函数进行估计求解,并给出了估计量的迭代计算过程;最后,对本文的研究内容进行了总结与展望。     

The Confidence Ellipses in Decomposition Multiple Non Symmetric Correspondence Analysis

Non Symmetric Correspondence Analysis (NSCA) (D'Ambra and Lauro, 1989 D'Ambra , L. , Lauro , N. ( 1989 ). Non symmetrical analysis of three way contingency tables . In: Multiway Data Analysis , Coppi , R. , Bolasco , S. , Eds., North Holland , Amsterdam : pp. 301 – 315 . [Google Scholar]) is a useful technique for analyzing a two-way contingency table.

The key difference between the symmetrical and non symmetrical versions of correspondence analysis rests on the measure of the association used to quantify the relationship between the variables. For a two-way, or multi-way, contingency table, the Pearson chi-squared statistic is commonly used when it can be assumed that the categorical variables are symmetrically related. However, for a two-way table, it may be that one variable can be treated as a predictor variable and the second variable can be considered as a response variable.

Yet, for such a variable structure, the Pearson chi-squared statistic is not an appropriate measure of the association. Instead, one may consider the Goodman-Kruskal tau index. In the case that there are more than two cross-classified variables, multivariate versions of the Goodman-Kruskal tau index can be considered. These include Marcotorchino's index (Marcotorchino, 1985) and Gray-Williams’ index (Gray and Williams, 1975 Gray , L. N. , Williams , J. S. ( 1975 ). Goodman and Kruskals Tau B: Multiple and partial analogy. Amer. Statist. Assoc. Proc. Soc. Statist. Sec. pp. 444 – 448 . [Google Scholar]).

In this article, the Multiple non Symmetric Correspondence Analysis (MNSCA), along with the decomposition of the TAU by Gray-Williams in main effects and interaction (D'Ambra et al., 2011 D'Ambra , L. , D'Ambra , A. , Sarnacchiaro , P. ( 2011 ). Visualising main effects and interaction term in multiple non symmetric correspondence analysis. Submitted.  [Google Scholar]), is used for the evaluation of the innovative performance of the manufacturing enterprises in Campania.

Finally, to identify a category which is statistically significant, the confidence ellipses have been proposed for the Multiple Non Symmetric Correspondence Analysis starting from the ellipses suggested by Beh (2010 Beh , E. J. ( 2010 ). Elliptical confidence regions for simple correspondence analysis . J. Statisti. Plann. Infer. [Web of Science ®] , [Google Scholar]) for the symmetrical analysis.     

A Reinforced Randomized Block Design with Correlated Errors

In the analysis of variance the errors are assumed to be independent which may not always be true. In this article, a restricted randomized block design under compound autocorrelated structure is considered. A method of analysis for such a randomized block design has been developed. It provides confidence ellipsoid and confidence interval of a set of estimable functions and an estimable function of treatment parameters, respectively. Analogous to Scheffe's method, the multiple comparison technique of judging all possible treatment contrasts has been derived. In the process, a method of estimation of unknown parameters has been also developed. An example (simulated data) illustrates this approach.     

Optimal designs for stated choice experiments that incorporate ties

In 1970 Davidson generalised the Bradley–Terry model to allow respondents to say that the two options presented in a choice task were equally attractive. In this paper we extend this idea to the MNL model with m options in each choice set and we show that the optimal designs for the MNL model are also optimal in this setting.     

Comparing multiple treatments to both positive and negative controls

In the past, most comparison to control problems have dealt with comparing k test treatments to either positive or negative controls. Dasgupta et al. [2006. Using numerical methods to find the least favorable configuration when comparing k test treatments to both positive and negative controls. Journal of Statistical Computation and Simulation 76, 251–265] enumerate situations where it is imperative to compare several test treatments to both a negative as well as a positive control simultaneously. Specifically, the aim is to see if the test treatments are worse than the negative control, or if they are better than the positive control when the two controls are sufficiently apart. To find critical regions for this problem, one needs to find the least favorable configuration (LFC) under the composite null. In their paper, Dasgupta et al. [2006. Using numerical methods to find the least favorable configuration when comparing k test treatments to both positive and negative controls. Journal of Statistical Computation and Simulation 76, 251–265] came up with a numerical technique to find the LFC. In this paper we verify their result analytically. Via Monte Carlo simulation we compare the proposed method to the logical single step alternatives: Dunnett's [1955. A multiple comparison procedure for comparing several treatments with a control. Journal of the American Statistical Association 50, 1096–1121] or the Bonferroni correction. The proposed method is superior in terms of both the Type I error and the marginal power.     

思维类型辨析

关于思维类型问题目前我国学界尚缺乏准确统一的界定。思维活动是由多种要素构成的复杂系统,根据其组成要素的性质不同,可以列出不同的分类标准,从而对思维进行比较全面的分类。根据思维的元素分为动作思维、意象思维和概念思维;其中除动作思维仍沿用惯称外,以“意象思维”取代习用的“形象思维”,以“概念思维”取代习用的“抽象思维”,更为确切。多元思维是同时以多种不同组分作为思维元素的思维,在此谨供探讨。     

论科技资源共享管理机关的设置与职权配置

为了有效执行有关科技资源共享的法律、法规及政策,必须建立一个高效的管理机关。然而,科技资源共享涉及众多部门,牵涉利益巨大。科技资源共享管理机关必须与其他科技管理机关的职责相协调。在目前的情况下,设立科技资源共享管理机构需要首先考虑科技资源多头管理模式的现实及其改革路径。具体的方法应当是建立高层次、多部门参加的科技资源共享决策协调机构,并相对集中执行权。同时,在职权设定上应当尽量配置规划、指导、资助等职权。     

Network effects on organizational decision-making: Blended social mechanisms and IPO withdrawal

This paper develops a new approach to the study of network effects in organizations and markets by proposing that structural influences on social and economic action result from contingent blends of well-understood social mechanisms. We emphasize the interplay of three different network processes: resource and information transfer, status signaling and certification, and social influence. Different mixes of these mechanisms characterize disparate networks because the obligations imposed by ties and the capacities of partners result in situations where mechanisms amplify or diminish one another. We test hypotheses about mechanism interactions using four years (1997–2000) of data on high-technology IPOs that situate organizational decisions about whether to withdraw an offering in two distinct networks. We find that network mechanisms exert multiple moderating effects on one another and that those effects vary systematically across venture capital syndicate and director interlock networks. These findings help to explain why different networks exert disparate effects, why the effects of some structures change as their larger contexts shift, and why even very successful organizations can sometimes find themselves hamstrung by their connections.     

The impact of Multiple Mini Interviews on the attrition and academic outcomes of midwifery students

BackgroundAdmission to the Bachelor of Midwifery (BMid) in Australia has traditionally been based on academic ranking. The BMid is a high demand course offered to a limited number of students and therefore choosing applicants who complete the degree is important. Multiple Mini Interviews (MMIs) are used to assess non-cognitive skills and select students into healthcare degrees. One university in Australia has introduced MMIs as part of the application process for the BMid.AimCompare attrition rates and Grade Point Average (GPA) scores between students admitted into the BMid using both academic ranking and MMIs, to those admitted on academic ranking alone.MethodsA basic convergent mixed methods design, using an explanatory unidirectional framework to integrate data. Attrition rates, GPA, and multiple mini interview scores (2013–2019), were linked and compared for before and after the use of MMI’s. Focus groups with students, interviewers, and hospital-based educators, explored stakeholder experiences. Open-ended questions from an applicant survey were added to the qualitative data set, which was analysed thematically.FindingsStudents who enrolled via the MMI’s had significantly lower attrition rates than those enrolled before MMI’s were introduced. GPA scores were significantly higher for students who enrolled via the MMI’s. Integration of data found MMI’s identified students passionate to undertake midwifery, and that success at the interviews increased students’ confidence to successfully complete their studies.ConclusionMMI’s as part of the entry process into the BMid enabled identification of applicants more likely to remain in the course and succeed in their studies.