Updating discriminant functions estimated from inverse gaussian populations

The problem of updating discriminant functions estimated from inverse Gaussian populations is investigated in situations when the additional observations are mixed (unclassified) or classified. In each case two types of discriminant functions, linear and quadratic, are considered. Using simulation experiments the performance of the updating procedures is evaluated by means of relative efficiencies.     

Covariate Adjusted Correlation Analysis via Varying Coefficient Models

Abstract.  We propose covariate adjusted correlation (Cadcor) analysis to target the correlation between two hidden variables that are observed after being multiplied by an unknown function of a common observable confounding variable. The distorting effects of this confounding may alter the correlation relation between the hidden variables. Covariate adjusted correlation analysis enables consistent estimation of this correlation, by targeting the definition of correlation through the slopes of the regressions of the hidden variables on each other and by establishing a connection to varying-coefficient regression. The asymptotic distribution of the resulting adjusted correlation estimate is established. These distribution results, when combined with proposed consistent estimates of the asymptotic variance, lead to the construction of approximate confidence intervals and inference for adjusted correlations. We illustrate our approach through an application to the Boston house price data. Finite sample properties of the proposed procedures are investigated through a simulation study.     

Time and support do not heal all wounds: Mental health correlates of past bullying among college students

Abstract

Objective: We examined whether perceptions of being bullied during middle and high school were associated with depressive, anxiety, and posttraumatic stress disorder (PTSD) symptoms during college. We also examined whether perceived social support (PSS) mediated the association between bullying and symptoms, and explored whether parental, peer, or other sources of support was most beneficial. Participants: Undergraduates (N?=?270) from an urban commuter college in the Northeast participated during Spring 2013 or Fall 2015. Methods: Psychometrically sound self-report measures were used to assess symptoms and perceptions of bullying and social support. Results: As hypothesized, bullying was associated with more symptoms, and PSS significantly mediated the associations between bullying and symptoms of PTSD and depression. Conclusion: The college years provide another opportunity to address the effects of middle and high school bullying. Receiving current support for past bullying is beneficial but is not enough, college counseling services are needed to reduce symptoms.     

Computer integrated manufacturing applications in an automotive factory

Abstract

System integration is critical to development and implementation of CIM (computer integrated manufacture). This paper outlines the elements of the CIM system implementation strategy and deals with the representation of CIM implementation stages in TO FAS; which is a car manufacturing factory. In TOFA?, a pilot CIM project has been completed with success and other projects are in the development phase.     

Estimation of parameters in mixtures of inverse gaussian distributions

Iterative procedures are developed for finding maximum likelihood estimates of the parameters of mixtures of two inverse Gaussian distributions. The performance of the estimates based on small samples is studied by simulation experiments. Asymptotic efficiencies relative to estimates based on completely classified samples are also evaluated. Unless the components of the populations are widely separated, the maximum likelihood estimates perform poorly.     

Cost-benefit analysis—a critique

This paper surveys some of the main criticisms of cost-benefit analysis (CBA) that have emerged over the years. It is noted in passing that views on what type of technique CBA really is, or should be, have differed and continue to differ depending on the set of value judgements used. We emphasise that the more recent suggested extensions to or modifications of CBA have sought to make the technique more comprehensive (i.e. to include distributional, environmental quality and other objectives as well as economic efficiency) at the inevitable cost of a loss of precision. The underlying principles of CBA are examined and the problems of multiple objective planning highlighted. Valuation problems are analysed, in particular with regard to amenity and environmental effects. Finally, the issues of uncertainty, irreversibility and intergenerational equity are raised briefly to indicate the complexity of the decision-making task when large-scale technologically advanced projects have to be appraised. In conclusion it is argued that CBA presented in a disaggregated format, as a comprehensive method for the ordering of information and a testing procedure for a range of valuations can perform a useful role in the decision-making process. The term ‘policy analysis’ is probably a better one for this broader view of the use of CBA. Ultimately we seem to be searching for a synthesis of the participatory and the traditional (technocratic) style of decision-making though we have a long and difficult course to chart before we even approach such a goal.     

Errors of misclassification associated with the inverse gaussion distribution

Errors of misclassification and their probabilities are studied for classification problems associated with univariate inverse Gaussian distributions. The effects of applying the linear discriminant function (LDF), based on normality, to inverse Gaussian populations are assessed by comparing probabilities (optimum and conditional) based on the LDF with those based on the likelihood ratio rule (LR) for the inverse Gaussian, Both theoretical and empirical results are presented