Flexible models for non-equidispersed count data: comparative performance of parametric models to deal with underdispersion

AStA Advances in Statistical Analysis - Count data as response variables are commonly modeled using Poisson regression models, which require equidispersion, i.e., equal mean and variance. However,...     

Empirical likelihood tests for two‐sample problems via nonparametric density estimation

The authors study the problem of testing whether two populations have the same law by comparing kernel estimators of the two density functions. The proposed test statistic is based on a local empirical likelihood approach. They obtain the asymptotic distribution of the test statistic and propose a bootstrap approximation to calibrate the test. A simulation study is carried out in which the proposed method is compared with two competitors, and a procedure to select the bandwidth parameter is studied. The proposed test can be extended to more than two samples and to multivariate distributions.     

The International Crisis of Confidence in Corporations

Journal of Management and Governance -     

Technology,Gender and Time: A Contribution to the Debate

Using the data collected from research carried out at two Portuguese universities, this article highlights the way university lecturers currently deal with space and time. Their professional activity is not externally subjected to a specific time geometry that defines their working day. Teaching and researching time–spaces are basically task oriented. Furthermore, university lecturers are increasingly requested to perform tasks in very short time periods in order to secure financial support. To a certain extent, this pressure upon their work is facilitated by the use of technology. However, technology also causes a profound reconfiguration of working times and spaces, especially because it allows lecturers to work at any time from anywhere. This not only renders university physical spaces and times virtual, but it also leads to the colonization of several other time–spaces of their social lives. This article analyses the ambivalence and difficulty of managing time–spaces, as described by the lecturers themselves, with the objective of providing a more accurate awareness of the implications of technology on their lives, as well as the hazards of the progressive externalization of academic work, particularly for women.     

Rurality Index for Small Areas in Spain

An operational definition for “rural area” is pivotal if proposals, policies and decisions aimed at optimising the distribution of resources, closing the gap on inequity between areas and raising standards of living for the least advantaged populations are to be put in place. The concept of rurality, however, is often based on alternative and conflicting definitions, requiring clarification of the underlying theoretical model. Traditionally a geographical area has been classified as rural by taking into account either the number of inhabitants or population density. Two kinds of problem are raised with this approach, however, namely: it is inherently difficult to describe such a complex concept as rurality with a single variable; and reducing the concept down to a rural/urban dichotomy by setting a non-universal cut-off point does not usually provide an accurate account of reality. Within the context of the rural–urban continuum, this paper has devised a rurality index for Spanish municipalities based on the 1991 Population, Housing and Household Survey. The index was built on a principal components factor analysis, giving rise to a single factor that is correlated to the aging of the population, economic dependency, farming, livestock or fishing-related employment, habitability of housing and population density. A score to each municipality was allocated. This index can be regularly updated thus enabling the progress of the concept of rurality to be monitored in our setting over time and then compared with other countries using the same methods.     

Finite population prediction under a linear function superpopulation model:a bayesian perspective

Exact and approximate Bayesian inference is developed for the prediction problem in finite populations under a linear functional superpopulation model. The models considered are the usual regression models involving two variables, X and Y, where the independent variable X is measured with error. The approach is based on the conditional distribution of Y given X and our predictor is the posterior mean of the quantity of interest (population total and population variance) given the observed data. Empirical investigations about optimal purposive samples and possible model misspecifications based on comparisons with the corresponding models where X is measured without error are also reported.     

Waiting time to exhaust lottery numbers

Questions related to lotteries are usually of interest to the public since people think there is a magic formula which will help them to win lottery draws. This note shows how to compute the expected waiting time to observe specific numbers in a sequence of lottery draws and show that surprising facts are expected to occur.