Estimation of generalized exponential distribution based on an adaptive progressively type-II censored sample

In this paper, based on an adaptive Type-II progressively censored sample from the generalized exponential distribution, the maximum likelihood and Bayesian estimators are derived for the unknown parameters as well as the reliability and hazard functions. Also, the approximate confidence intervals of the unknown parameters, and the reliability and hazard functions are calculated. Markov chain Monte Carlo method is applied to carry out a Bayesian estimation procedure and in turn calculate the credible intervals. Moreover, results from simulation studies assessing the performance of our proposed method are included. Finally, an illustrative example using real data set is presented for illustrating all the inferential procedures developed here.     

The Role of Religiosity on the Relationship Between Materialism and Fashion Clothing Consumption Among Malaysian Generation Y Consumers

Religiosity is a significant cultural force influencing various dimensions of consumer behaviours; however, its role in the literature on fashion clothing remains unclear. To rectify this paucity of information, this study explores the relationship between religiosity, materialism and fashion clothing involvement (FCI); and religiosity, materialism and fashion clothing purchase involvement (FCPI). Using a sample of 282 Malaysian Generation Y consumers, it employs a positivist research approach, comprising of a quantitative basis of enquiry, and gathered data via survey questionnaires. The research findings show that religiosity moderates the relationship between materialism and FCI, as well as materialism and FCPI, where an individual’s religiosity is inversely associated with FCPI. Another finding is the importance of FCI in mediating the relationship between materialism and FCPI, plus the significance of mediated moderation and its effects on the relationship between materialism and FCPI. The findings reinforce the role of religiosity in consumer involvement in fashion clothing and fashion clothing purchase trends. Recognition of this significant construct and its importance may enable marketers to develop more sophisticated positioning strategies.     

On the b-coloring of tight graphs

A coloring c of a graph \(G=(V,E)\) is a b -coloring if for every color i there is a vertex, say w(i), of color i whose neighborhood intersects every other color class. The vertex w(i) is called a b-dominating vertex of color i. The b -chromatic number of a graph G, denoted by b(G), is the largest integer k such that G admits a b-coloring with k colors. Let m(G) be the largest integer m such that G has at least m vertices of degree at least \(m-1\). A graph G is tight if it has exactly m(G) vertices of degree \(m(G)-1\), and any other vertex has degree at most \(m(G)-2\). In this paper, we show that the b-chromatic number of tight graphs with girth at least 8 is at least \(m(G)-1\) and characterize the graphs G such that \(b(G)=m(G)\). Lin and Chang (2013) conjectured that the b-chromatic number of any graph in \(\mathcal {B}_{m}\) is m or \(m-1\) where \(\mathcal {B}_{m}\) is the class of tight bipartite graphs \((D,D{^\prime })\) of girth 6 such that D is the set of vertices of degree \(m-1\). We verify the conjecture of Lin and Chang for some subclass of \(\mathcal {B}_{m}\), and we give a lower bound for any graph in \(\mathcal {B}_{m}\).     

Behaviour of skewness, kurtosis and normality tests in long memory data

We establish the limiting distributions for empirical estimators of the coefficient of skewness, kurtosis, and the Jarque–Bera normality test statistic for long memory linear processes. We show that these estimators, contrary to the case of short memory, are neither ${\sqrt{n}}We establish the limiting distributions for empirical estimators of the coefficient of skewness, kurtosis, and the Jarque–Bera normality test statistic for long memory linear processes. We show that these estimators, contrary to the case of short memory, are neither ?n{\sqrt{n}}-consistent nor asymptotically normal. The normalizations needed to obtain the limiting distributions depend on the long memory parameter d. A direct consequence is that if data are long memory then testing normality with the Jarque–Bera test by using the chi-squared critical values is not valid. Therefore, statistical inference based on skewness, kurtosis, and the Jarque–Bera normality test, needs a rescaling of the corresponding statistics and computing new critical values of their nonstandard limiting distributions.     

Support vector regression based residual control charts

Control charts for residuals, based on the regression model, require a robust fitting technique for minimizing the error resulting from the fitted model. However, in the multivariate case, when the number of variables is high and data become complex, traditional fitting techniques, such as ordinary least squares (OLS), lose efficiency. In this paper, support vector regression (SVR) is used to construct robust control charts for residuals, called SVR-chart. This choice is based on the fact that the SVR is designed to minimize the structural error whereas other techniques minimize the empirical error. An application shows that SVR methods gives competitive results in comparison with the OLS and the partial least squares method, in terms of standard deviation of the error prediction and the standard error of performance. A sensitivity study is conducted to evaluate the SVR-chart performance based on the average run length (ARL) and showed that the SVR-chart has the best ARL behaviour in comparison with the other residuals control charts.     

Call for Papers for Two Thematic Issues

Call for Papers

Call for Papers for Two Thematic Issues     

Alcohol Consumption Decisions in Korea

Data from the 1996 Korean Household Panel Study and a double-hurdle model were used to analyze alcohol consumption decisions in Korea. The Korean most likely to consume alcoholic beverages is a young male, and a college graduate. Among those who drink, being older, male, self-employed, or a farm or fishery worker were positively associated, and higher education levels were negatively associated with consumption level. The findings for gender and education were generally similar to those of studies using U.S. or Canadian data on alcohol consumption. The role of household level economic factors, family composition, and residence in alcohol consumption decisions appears to differ across cultures, however.     

Redistribution Through Education and Other Mechanisms Under Capital‐Market Imperfections and Uncertainty: A Welfare Effect Analysis

Abstract. This paper considers a two‐period model of endogenous human capital formation under the credits‐market imperfection and uncertainty assumptions. We compare in the first part of the paper ex‐ante and ex‐post general‐equilibrium effects of the education subsidy policy to those of the negative income tax and the unskilled wage subsidy regimes. We show that the education subsidy policy raises an efficiency‐inequality trade‐off issue, and therefore it is optimal unless the degree of inequality aversion is relatively high and financing the subsidy is not too distorsive. Public loans are generally claimed to provide a solution for such issue. We explore the implications of implementing the public loan under several schemes in the second part of the paper. We show that combining between a pure public loan and education subsidies provides higher levels of welfare than these two policies taken separately provided that the inequality aversion degree is high. For low degrees of inequality aversion, the pure public loan is the optimal policy.     

Study of Cases of Child Sexual Abuse Referred for Medico-Legal Examination in Cairo and Giza,Egypt,2007–2011

ABSTRACT

Child sexual abuse is a complex problem that results in detrimental effects on its victims. This study aimed to investigate the pattern of child sexual abuse in cases referred for medico-legal examination in Cairo and Giza governorates in the period between 2007–2011. The study included 813 cases of child sexual abuse. Female gender was more predominant than male gender (52.8%, 4.29 cases), and adolescents were the most frequent age group identified as victims of sexual abuse (43.8%, 356 cases). All perpetrators were male and most of them were persons outside the victims’ families (89.9%, 731 cases). It was recommended to teach and encourage children to tell their caregivers if they have been assaulted and to educate parents and caregivers on how to respond when the child discloses sexual abuse.