A class of symmetric bivariate uniform distributions

A class of symmetric bivariate uniform distributions is proposed for use in statistical modeling. The distributions may be constructed to be absolutely continuous with correlations as close to±1 as desired. Expressions for the correlations, regressions and copulas are found. An extension to three dimensions is proposed.     

The residual effect of a growth-decay mechanism and the distributions of covariance structures

The product of two independent or dependent scalar normal variables, sums of products, sample covariances, and general bilinear forms are considered. Their distributions are shown to belong to a class called generalized Laplacian. A growth-decay mechanism is also shown to produce such a generalized Laplacian. Sets of necessary and sufficient conditions are derived for bilinear forms to belong to this class. As a generalization, the distributions of rectangular matrices associated with multivariate normal random vectors are also discussed.     

Politics and Scientific Expertise: Scientists, Risk Perception, and Nuclear Waste Policy

To study the homogeneity and influences on scientists'perspectives of environmental risks, we have examined similarities and differences in risk perceptions, particularly regarding nuclear wastes, and policy preferences among 1011 scientists and engineers. We found significant differences ( p 0.05)in the patterns of beliefs among scientists from different fields of research. In contrast to physicists, chemists, and engineers, life scientists tend to: (a)perceive the greatest risks from nuclear energy and nuclear waste management; (b)perceive higher levels of overall environmental risk; (c)strongly oppose imposing risks on unconsenting individuals; and (d)prefer stronger requirements for environmental management. On some issues related to priorities among public problems and calls for government action, there are significant variations among life scientists or physical scientists. We also found that–independently of field of research–perceptions of risk and its correlates are significantly associated with the type of institution in which the scientist is employed. Scientists in universities or state and local governments tend to see the risks of nuclear energy and wastes as greater than scientists who work as business consultants, for federal organizations, or for private research laboratories. Significant differences also are found in priority given to environmental risks, the perceived proximity of environmental disaster, willingness to impose risks on an unconsenting population, and the necessity of accepting risks and sacrifices.     

The identification of logistic regression models with errors in the variables

The simple logistic regression model with normal measurement error and normal regressor is shown to be identifiable without any extra information about the measurement error. The multiple logistic regression model with more than one regressor variable measured with error is not identifiable. If the covariance matrix of the measurement error is known up to a scalar factor, the model is identified. Further we discuss why in spite of the identifiability the models cannot be estimated in a reasonable way without extra information about the measurement error.     

On the run length of a Shewhart chart for correlated data

We consider an extension of the classical Shewhart control chart to correlated data which was introduced by Vasilopoulos/Stamboulis (1978). Inequalities for the moments of the run length are given under weak conditions. It is proved analytically that the average run length (ARL) in the in-control state of the correlated process is larger than that in the case of independent variables. The exact ARL is calculated for exchangeable normal variables and autoregressive processes (AR). Moreover, we compare this chart with residual charts. Especially, in the case of an AR(1)—process with positive coefficient, it turns out that the out-of-control ARL of the modified Shewhart chart is smaller than that of the Shewhart chart for the residuals.     

Useful relationship between the log-survival function and truncated moments,with applications

We present a new characterization technique extracted from a well known idea in statistical inference. We use the partial derivative of the logarithm of the survival function in connection with truncated moments to characterize several probability distributions. Our methods introduce a unified technique to obtain several well known results in a unified way.     

Towards a Coherent Policy of Co–Development

This paper seeks to demonstrate the major benefits that a dedicated policy of co–development can bring to three major actors affected by immigration: receiving states, countries of origin, and the immigrants themselves. True co–development involves sustained cooperation between receiving nations and source nations in the management of both legal and illegal migratory flows. At the same time, it fosters the economic and demographic development of both the sending and the receiving country. This cooperation is based in large measure on understanding that, more than ever before, the best migration policy for developed nations is one that seeks not to block, but to smoothly regulate the circulation and re–circulation of the majority of foreigners and immigrants. As a result, Northern countries will be able to concentrate the state’s limited control resources on selected targets such as criminals, delinquents, and migrants arrested multiple times for unauthorized entry or residence. Developed nations must recognize that the vast majority of immigrants wish to retain close links to their country of origin, and with drastically improved transportation and communication links, most migrants are increasingly able to do so. Northern states should adapt policies that, for the most part, accommodate immigrants’ wishes to maintain active ties to their homeland. Such measures are generally in the best interests of the receiving countries, source countries, and of course, the immigrants themselves. The various problems faced by these three main actors regarding migration as they seek to pursue activities in their best interest is considered, followed by the advantages that a policy of co–development has for these actors: for receiving nations in terms of meeting labour force needs, reducing demographic problems, and controlling illegal immigration; and for source countries in terms of increased access to visas, increased amounts and efficacy of remittances, and the return and re–circulation of skilled and seasonal workers, and retirees. The interests of the immigrants themselves will be considered at various points throughout the discussion, in the context of the effects that the various policies of receiving and sending countries will have on them.