Ergonomics and the inclusion of people with disabilities in a Brazilian workplace

The customization of a secretary workstation at a drama school was the objective of this case study. The investigation involved a 25-year-old illiterate woman with intellectual disabilities and low vision that had been been attending, for over 12 years, a state school for people with disabilities. The customization process, operationalized after a diagnosis was made, focused on environmental rearrangements, with the purpose of meeting the physical and social demands of the workstation. The results of this research are configured in an ergonomic analysis of work associated with an inventory of social skills, applied to people living directly with the participant. Preliminary evaluations indicated the degree of adjustment of labor demands to the personal characteristics of the participant in the customized job.     

On the asymptotic distribution of Cook's distance in logistic regression models

It sometimes occurs that one or more components of the data exert a disproportionate influence on the model estimation. We need a reliable tool for identifying such troublesome cases in order to decide either eliminate from the sample, when the data collect was badly realized, or otherwise take care on the use of the model because the results could be affected by such components. Since a measure for detecting influential cases in linear regression setting was proposed by Cook [Detection of influential observations in linear regression, Technometrics 19 (1977), pp. 15–18.], apart from the same measure for other models, several new measures have been suggested as single-case diagnostics. For most of them some cutoff values have been recommended (see [D.A. Belsley, E. Kuh, and R.E. Welsch, Regression Diagnostics: Identifying Influential Data and Sources of Collinearity, 2nd ed., John Wiley & Sons, New York, Chichester, Brisban, (2004).], for instance), however the lack of a quantile type cutoff for Cook's statistics has induced the analyst to deal only with index plots as worthy diagnostic tools. Focussed on logistic regression, the aim of this paper is to provide the asymptotic distribution of Cook's distance in order to look for a meaningful cutoff point for detecting influential and leverage observations.     

PEER PRESSURE: EXPERIMENTAL EVIDENCE FROM RESTROOM BEHAVIOR

We provide experimental evidence on the effect of peer pressure on individual behavior. Specifically, we study the effect of being exposed to an observer in a public restroom on handwashing and urinal flushing behavior. Our estimates show that being exposed to an observer increases the probability of handwashing by 13 percentage points and the probability of urinal flushing by 15 percentage points. Given that handwashing and urinal flushing have social benefits that exceed individual benefits, our findings provide support for peer pressure as an additional way of addressing the social suboptimality arising from externalities. (JEL C91, C93)     

Robust Wald-type tests in GLM with random design based on minimum density power divergence estimators

Statistical Methods & Applications - We consider the problem of robust inference under the generalized linear model (GLM) with stochastic covariates. We derive the properties of the minimum...     

Shortcomings in the Measurement of Innovation: Implications for Accounting Standard Setting

Innovation is nowadays a fundamental determinant of value creation in business companies and economic growth. Therefore, the measurement of innovation has become a significant concern both for business companies and governments. Traditionally, attempts to measure innovation have adopted a macroeconomic approach, as they have been largely based on broad surveys. However, no attempt has been made to date in order to complement the information provided by such surveys with aggregated data obtained from the financial reports of individual companies. This paper analyses the conceptual and methodological problems underlying the measurement of business innovation by means of surveys and discusses the lack of ability of accounting standards to accurately reflect innovative activities in the financial statements of business firms.In the light of the evidence provided by the empirical studies published to date, we analyse the Spanish situation by reviewing innovation studies conducted by the National Institute of Statistics (INE), and assessing the relationship between the value relevance of accounting information and the firm's technological level. Our results suggest that both, micro- and macroeconomic approaches towards the measurement of innovation have significant shortcomings. Thus, a joint effort seems to be needed in order to overcome the methodological limitations affecting innovation studies based on surveys and those relying on financial accounting information. Despite their limitations, surveys provide a sound basis for the identification of trends, key factors and explanatory variables. On the other hand, financial statements could provide a sound basis for the measurement of innovation if they included more relevant information on the intangible determinants of the value of companies. This has obvious implications for the standard setting process.     

Ergonomics at Volkswagen Brasil. Multidisciplinary work to equalize health, productivity and quality

Following the technological developments and presented to the multidisciplinary processes as automakers, Volkswagen Brazil, represented by its ergonomists, through this paper, shows the importance of ergonomic efficiency of management applied to various levels of life of a product, since its creation to its final implementation on production lines.The preventive work of ergonomists during the processes leading to production of a vehicle is accomplished through assessments on a simulated system called the Digital Factory. Since the initial stages to final product delivery there is a need for a multidisciplinary aligning the concepts of ergonomics, productivity and quality of product. Industrial Engineering, Process Engineering, ergonomists and workers are involved in the analysis made through the Workshop's showing the importance of discussion between the various users of the systems. The processes of series are also equipped with a set of certifications flow of job and planned audits on items that describe processes and applied ergonomics.     

Rényi statistics for testing equality of autocorrelation coefficients

The problem of testing for equality of autocorrelation coefficients of two populations in multivariate data when errors are autocorrelated is considered. We derive Rényi statistics defined as divergences between unrestricted and restricted estimated joint probability density functions and we show that they are asymptotically chi-square distributed under the null hypothesis of interest. Monte Carlo simulation experiments are carried out to investigate the behavior of Rényi statistics and to make comparisons with test statistics based on the approach of Bhandary [M. Bhandary, Test for equality of autocorrelation coefficients for two populations in multivariate data when the errors are autocorrelated, Statistics & Probability Letters 73 (2005) 333–342] for the problem under consideration. Rényi statistics showed to have significantly better behavior.     

Fitting DNA sequences through log-linear modelling with linear constraints

For some discrete state series, such as DNA sequences, it can often be postulated that its probabilistic behaviour is given by a Markov chain. For making the decision on whether or not an uncharacterized piece of DNA is part of the coding region of a gene, under the Markovian assumption, there are two statistical tools that are essential to be considered: the hypothesis testing of the order in a Markov chain and the estimators of transition probabilities. In order to improve the traditional statistical procedures for both of them when stationarity assumption can be considered, a new version for understanding the homogeneity hypothesis is proposed so that log-linear modelling is applied for conditional independence jointly with homogeneity restrictions on the expected means of transition counts in the sequence. In addition we can consider a variety of test-statistics and estimators by using φ-divergence measures. As special case of them the well-known likelihood ratio test-statistics and maximum-likelihood estimators are obtained.     

A Necessary Power Divergence Type Family Tests of Multivariate Normality

In a recent article, Cardoso de Oliveira and Ferreira have proposed a multivariate extension of the univariate chi-squared normality test, using a known result for the distribution of quadratic forms in normal variables. In this article, we propose a family of power divergence type test statistics for testing the hypothesis of multinormality. The proposed family of test statistics includes as a particular case the test proposed by Cardoso de Oliveira and Ferreira. We assess the performance of the new family of test statistics by using Monte Carlo simulation. In this context, the type I error rates and the power of the tests are studied, for important family members. Moreover, the performance of significant members of the proposed test statistics are compared with the respective performance of a multivariate normality test, proposed recently by Batsidis and Zografos. Finally, two well-known data sets are used to illustrate the method developed in this article as well as the specialized test of multivariate normality proposed by Batsidis and Zografos.