A robust estimation method for the linear regression model parameters with correlated error terms and outliers

Independence of error terms in a linear regression model, often not established. So a linear regression model with correlated error terms appears in many applications. According to the earlier studies, this kind of error terms, basically can affect the robustness of the linear regression model analysis. It is also shown that the robustness of the parameters estimators of a linear regression model can stay using the M-estimator. But considering that, it acquires this feature as the result of establishment of its efficiency. Whereas, it has been shown that the minimum Matusita distance estimators, has both features robustness and efficiency at the same time. On the other hand, because the Cochrane and Orcutt adjusted least squares estimators are not affected by the dependence of the error terms, so they are efficient estimators. Here we are using of a non-parametric kernel density estimation method, to give a new method of obtaining the minimum Matusita distance estimators for the linear regression model with correlated error terms in the presence of outliers. Also, simulation and real data study both are done for the introduced estimation method. In each case, the proposed method represents lower biases and mean squared errors than the other two methods.KEYWORDS: Robust estimation method, minimum Matusita distance estimation method, non-parametric kernel density estimation method, correlated error terms, outliers     

On the incidence–prevalence relation and length‐biased sampling

For many diseases, logistic constraints render large incidence studies difficult to carry out. This becomes a drawback, particularly when a new study is needed each time the incidence rate is investigated in a new population. By carrying out a prevalent cohort study with follow‐up it is possible to estimate the incidence rate if it is constant. The authors derive the maximum likelihood estimator (MLE) of the overall incidence rate, λ, as well as age‐specific incidence rates, by exploiting the epidemiologic relationship, (prevalence odds) = (incidence rate) × (mean duration) (P/[1 ? P] = λ × µ). The authors establish the asymptotic distributions of the MLEs and provide approximate confidence intervals for the parameters. Moreover, the MLE of λ is asymptotically most efficient and is the natural estimator obtained by substituting the marginal maximum likelihood estimators for P and µ into P/[1 ? P] = λ × µ. Following‐up the subjects allows the authors to develop these widely applicable procedures. The authors apply their methods to data collected as part of the Canadian Study of Health and Ageing to estimate the incidence rate of dementia amongst elderly Canadians. The Canadian Journal of Statistics © 2009 Statistical Society of Canada     

Biased sampling with right censoring: A note on sun,Cui & Tiwari (2002)

Sun, Cui & Tiwari (2002) studied the asymptotic behaviour of certain goodness‐of‐fit tests in the presence of biased sampling and right censoring. The author illustrates that unfortunately, an assumption made by Sun, Cui and Tiwari on the independence between failure and censoring time fails to hold in many important applications, which limits the applicability of their results.     

An analysis of major social obstacles affecting human resource development in Iran

ABSTRACT

This study aimed to analyze the major social obstacles affecting the human resource development (HRD) in Iran. The study population included faculty members in Yazd province, Iran (N = 280, n = 162). A survey and a researcher-made questionnaire were used to collect data. The reliability of the questionnaire was confirmed by using Cronbach’s alpha (0.88) and its validity was approved by a panel of experts. The results indicated that the major social obstacles affecting HRD are ‘an increase in the share of foreigners in the labor market’, ‘frustration of native graduates’ and ‘local brain drain’, respectively. Furthermore, the results of exploratory factor analysis indicated that the most important social obstacles affecting HRD can be summarized into six factors including migration, lack of nativism, inclination towards foreigners, gender imbalance, lack of justice in distribution of resources, and lack of meritocracy. These factors altogether could explain 65.45% of the total variance. In the end, some applied recommendations (such as paying more attention to rural youth, fair distribution of facilities towards urban and rural balance, supporting native elites, preference for employment, and applying indigenous peoples based on meritocracy, creating favorable balance at different levels of academic education, avoiding gender inequality) have been presented.     

A traffic congestion analysis by user equilibrium and system optimum with incomplete information

Journal of Combinatorial Optimization - Nowadays, the rapid development of intelligent navigation systems has profound impacts on the routing of traffic users. With the assistance of these...     

The role of educational institutions in the clientization of immigrants: The Swedish case

European nations are multicultural societies. Multiculturalism is more a part of these countries' intellectual debates, however, than part of their policies and practices. The public and governmental sectors of Europe still remain monocultural. Monoculturalism, which entails the cultural hegemony of the ‘white majority’ of European societies over ‘other’ cultural groups, is a part of the systematic reproduction of an established social order. Formal education is an important means of reproduction of the monocultural order. European monoculturalism is based on an ethnocentrism that has a long tradition in the Western worldview and is institutionalized in its political, judicial, educational and bureaucratic systems. Western monoculturalism has become increasingly problematic in the face of growing multiculturalism in Europe and jeopardizes the existing social order. The integration of diverse immigrant groups into the host societies is not compatible with the reproduction of Western cultural hegemony, a hegemony through which the policy of integration is simply reduced to a political goal that limits immigrants' action to that of adjusting themselves to objective norms and rules. Monoculturally educated groups, who are supposed to help immigrants become integrated into such societies, paradoxically construct obstacles to their integration.     

Theorizing morality in context

How does context condition morality? This is one of the core questions of the sociology of morality and also one that has remained largely untheorized till date. In this article, we draw on insights from symbolic interactionism, and develop a theoretical framework that highlights the role of context in variation of morality. This framework is informed by a view of the self as a reflexive process that engages with moral norms through giving a self-account in relation to the norms. Based on this view, we distinguish between three contextual dimensions that condition morality: symbolic forms, scenes of address, and narrating subjects. The article concludes with a discussion of the implications of the presented theoretical framework for sociological studies of morality.     

Distorted integration: Problems of monolithic order

For generating a theory of integration in today's modem multicultural societies, we must go beyond reductionists’ ‘objective’ interpretations and instead use a concept of social solidarity based on individuals’ loyally to society and its values. The matter of integration cannot be reduced to a process of adoption of the host societies’ ‘norms’ and ‘values’ by immigrants. Such a process does not completely change the people's lifestyles, but it modifies them. One of the most important characteristics of integrated society has to do with the individuals’ active participation in the production and reproduction of their own life with little or no dependence on state subsidies.     

Social Participation, Sense of Community and Social Well Being: A Study on American, Italian and Iranian University Students

Aim of the study was to assess the relationship between social participation and Sense of Community in a sample of University students and the impact of such variables on Social well being. A further aim was to assess the generality of the relationships between these constructs across different countries, and specifically, the USA, Italy and Iran. The sample includes 200 Italian, 125 American and 214 Iranian University students, male and female. Results show higher levels of social participation, Sense of Community and Social well being among American students. Sense of Community is positively correlated with social participation in all three samples; however, only among Italian students social participation positively predicts Social well being. Implications of results will be discussed.