Optimal two treatment repeated measurement designs for three periods

Repeated Measurement Designs, with two treatments, n (experimental) units and p periods are examined, the two treatments are denoted A and B. The model with independent observations within and between treatment sequences is used. Optimal designs are derived for: (i) the difference of direct treatment effects and the difference of residual effects, (ii) the difference of direct treatment effects, and (iii) the difference of residual effects. We prove that for three periods when n is odd the optimal design in the three cases (i), (ii), and (iii) is determined by taking the sequences BAA and ABB in numbers differing by one. If n is even, the optimal design in cases (i), (ii), and (iii) is again the same, by taking the sequences ABB and BAA in equal numbers. In case (i), for n even or odd, in the optimal design there is no correlation between the two estimated parameters. For n even, case (i) was solved by Cheng and Wu in 1980. The above imply that with two treatments in practice are preferable to use three periods instead of two.     

Goodness-of-Fit Tests Based on Correcting Moments of Entropy Estimators

In this article, we consider the entropy estimator introduced by Alizadeh Noughabi and Arghami (2010) and derive the nonparametric distribution function corresponding to our estimator as a piece-wise uniform distribution. We use the results to introduce goodness-of-fit tests for the normal and the exponential distributions. The critical values and powers for some alternatives are obtained by simulation. The powers of the proposed tests under various alternatives are compared with the competitors.     

Power Law Selection Model for Repairable Systems

A repairable system, under minimal repair, is usually modeled according to a Non-Homogeneous Poisson Process (NHPP) assuming a Power Law intensity function. A traditional approach considers iid NHPPs in order to conduct a statistical analysis based on a sample of systems. However, systems might be heterogeneous due to unmeasured variables such as age, suppliers, and so on. In order to verify this assumption a frequentist approach is proposed in this article. Some possible model scenarios considering different systems heterogeneity are compared using likelihood ratio tests and information criteria. Real data sets illustrate the proposed methodology.     

A generalized model of logistic regression for clustered data

This paper proposes a generalized logistic regression model that can account for the correlation among responses on subunits. The subunits may arise as data on multiple observations within an individual. This method generalizes earlier work by Rosner (1984 a,b) and others. Methodological generalizations include: (1) the use of the more general Polya-Eggenberger distribution instead of the beta-binomial distribution to model the correlation structure, so that cases with negative, positive, or zero intraclass correlation can be handled; (2) a stepwise approach; (3) linear and non-linear regression; and, (4) the inclusion of the case of a truncated distribution. The model can accommodate missing data and covariates on the unit and subunit level. The derivative-free simplex algorithm is used to estimate the parameters.

The model is applied to data describing the progression of obstruction in coronary disease where multiple arterial segments are studied for each patient. The correlation in response that may exist for these multiple segments is accounted for in the analyses while attempting to examine associations with individual-specific (e.g., history of diabetes) and segment-specific (e.g., initial percent stenosis) covariates. Analyses were performed on a data set describing 382 patients with unoperated coronary artery disease and two coronary angiograms separated by at least one month and on a data set describing 284 patients undergoing percutaneous transluminal coronary angioplasty and studied by coronary angiograms.     

Estimates of the parameters of type-II extreme value distribution from censored samples

Maximum likelihood estimators of a Type-II extreme value distribution are derived from doubly censored samples. The asymptotic variances and covariances of the maximum likelihood estimators are discussed and these are numerically evaluated for different censoring proportions q₁ = 0.0(0. l) (0.9) from below and q₂ = 0.0 (0. l) (0.9- q₁) from above. The asymptotic relative efficiencies of the parameter estimates revealed that lower order statistics are more important for estimating the parameters of Type-II extreme value distribution as compared to higher order statistics.     

Estimation in M/Er /1 queueing systems

In this paper, the maximum likelihood estimates of the parameters for the M/E_r /1 queueing model are derived when the queue size at each departure point is observed. A numerical example is generated by simulating a finite Markov chain to illustrate the methodology for estimating the parameters with variable Erlang service time distribution. The problem of hypothesis testing and simultaneous Confidence regions of the parameter is also investigated.0     

Media reputation in initial public offerings: A study of financial news coverage in Hong Kong

This study investigated media reputation in initial public offerings (IPOs) by proposing eight attributes of substantive media reputation from environmental and product-resource perspectives. A content analysis on financial news coverage (2281 newspaper articles from 2004 to 2010) in Hong Kong was conducted to examine how print media reported financial and nonfinancial information on 38 IPO firms in the sectors of financial, properties and construction, and consumer goods. Results from partial least squares analysis showed that, although substantive media reputation and recency of news coverage together only explained a small proportion of changes in IPO share price, substantive media reputation has a significant positive effect on changes in IPO share price. Apart from the significant positive effect from the presentation tone of environmental attributes, the tone of social attributes had a significant negative effect on substantive media reputation. With the increasing concern on measuring media reputation attributes in financial news coverage across different contexts, this study contributes to the applicability of environmental and product-resource attributes in the specific context of IPOs.     

Diversity-The Competitive Advantage

ABSTRACT

There is increasing pressure on social service agencies to produce “results,” and often agency computer information systems are associated with efforts to do so. The current study explores worker characteristics that may interact with organizational factors in influencing data system utilization. A survey of 245 community social workers serving as field instructors was conducted. Worker skill and experience with computers accounted for a large part of the variance on the utilization of information systems followed by the user-friendliness of the system and the workers' beliefs that data are useful in their work. The findings suggest that organizations seeking to increase worker utilization of information systems will need to focus on enhancing worker's computer skills as well as assuring that the information is easy to use and is perceived as useful by workers.     

Diagnostics for multivariate imputations

Summary.  We consider three sorts of diagnostics for random imputations: displays of the completed data, which are intended to reveal unusual patterns that might suggest problems with the imputations, comparisons of the distributions of observed and imputed data values and checks of the fit of observed data to the model that is used to create the imputations. We formulate these methods in terms of sequential regression multivariate imputation, which is an iterative procedure in which the missing values of each variable are randomly imputed conditionally on all the other variables in the completed data matrix. We also consider a recalibration procedure for sequential regression imputations. We apply these methods to the 2002 environmental sustainability index, which is a linear aggregation of 64 environmental variables on 142 countries.     

基于中国实际的社会保障宏观核算机理研究

 目前,中国社会保障的宏观核算不能适应社会保障发展的需要,本文认为在中国开展社会保障核算既有必要性,也有现实可行性。本文参照SNA的一般原理与国际社会保障核算的经验,基于中国实际,对社会保障核算的核算对象、基本原理以及核算方法进行了讨论,并就中国特有的社会保障制度（即统账结合制度以及单位负责制）下的核算方法进行了探讨。