Optimal progressive group censoring scheme under cost considerations for pareto distribution

In this article, optimal design under the restriction of pre-determined budget of experiment is developed for the Pareto distribution when the life test is progressively group censored. We use the maximum-likelihood method to obtain the point estimator of the Pareto parameter. We propose two approaches to decide the number of test units, the number of inspections, and the length of inspection interval under limited budget such that the asymptotic variance of estimator of Pareto parameter is minimum. A numerical example is given to illustrate the proposed method. Some sensitivity analysis is also studied.     

Bayesian Analysis of Instrumental Variable Models: Acceptance-Rejection within Direct Monte Carlo

We discuss Bayesian inferential procedures within the family of instrumental variables regression models and focus on two issues: existence conditions for posterior moments of the parameters of interest under a flat prior and the potential of Direct Monte Carlo (DMC) approaches for efficient evaluation of such possibly highly non-elliptical posteriors. We show that, for the general case of m endogenous variables under a flat prior, posterior moments of order r exist for the coefficients reflecting the endogenous regressors’ effect on the dependent variable, if the number of instruments is greater than m +r, even though there is an issue of local non-identification that causes non-elliptical shapes of the posterior. This stresses the need for efficient Monte Carlo integration methods. We introduce an extension of DMC that incorporates an acceptance-rejection sampling step within DMC. This Acceptance-Rejection within Direct Monte Carlo (ARDMC) method has the attractive property that the generated random drawings are independent, which greatly helps the fast convergence of simulation results, and which facilitates the evaluation of the numerical accuracy. The speed of ARDMC can be easily further improved by making use of parallelized computation using multiple core machines or computer clusters. We note that ARDMC is an analogue to the well-known “Metropolis-Hastings within Gibbs” sampling in the sense that one ‘more difficult’ step is used within an ‘easier’ simulation method. We compare the ARDMC approach with the Gibbs sampler using simulated data and two empirical data sets, involving the settler mortality instrument of Acemoglu et al. (2001 Acemoglu , D. , Johnson , S. , Robinson , J. A. ( 2001 ). The colonial origins of comparative development: An empirical investigation . American Economic Review 91 ( 5 ): 1369 – 1401 .[Crossref], [Web of Science ®] , [Google Scholar]) and father's education's instrument used by Hoogerheide et al. (2012a Hoogerheide , L. F. , Block , J. H. , Thurik , A. R. (2012a). Family background variables as instruments for education in income regressions: A Bayesian analysis. Economics of Education Review 31(5):515–523.[Crossref], [Web of Science ®] , [Google Scholar]). Even without making use of parallelized computation, an efficiency gain is observed both under strong and weak instruments, where the gain can be enormous in the latter case.     

Remittances and Energy Consumption: Evidence from Morocco

The main purpose of this study is to empirically investigate the co‐integration and causal relationship between international remittances and energy consumption in the context of Morocco. Previous empirical studies associated remittances with various macroeconomic and social variables. To our knowledge, this is the first study that examines the causality between remittances and energy consumption in Morocco. The study finds a long‐run equilibrium relationship between remittances and energy consumption. The results indicate that remittances influence energy consumption directly both in the short run and long run, and influence energy consumption indirectly through industrialization and economic growth in the long run.     

Stabilizing heteroscedasticity for butterfly-distributed residuals by the weighting absolute centered external variable

In the current study, a new method by the weighting absolute centered external variable (WCEV) was proposed to stabilize heteroscedasticity for butterfly-distributed residuals (BDRs). After giving brief information about heteroscedasticity and BDRs, WCEV was introduced. The WCEV and commonly used variance stabilizing methods are compared on a simple and a multiple regression model. The WCEV was also tested for other type of heteroscedasticity patterns. In addition to heteroscedasticity, other regression assumptions were checked for the WCEV.     

A modified ridge m-estimator for linear regression model with multicollinearity and outliers

The ordinary least-square estimators for linear regression analysis with multicollinearity and outliers lead to unfavorable results. In this article, we propose a new robust modified ridge M-estimator (MRME) based on M-estimator (ME) to deal with the combined problem resulting from multicollinearity and outliers in the y-direction. MRME outperforms modified ridge estimator, robust ridge estimator and ME, according to mean squares error criterion. Furthermore, a numerical example and a Monte Carlo simulation experiment are given to illustrate some of the theoretical results.     

A comparison of count data models with an application to daily cigarette consumption of young persons

The objective of this study is providing a comparative assessment for researchers to deal with the challenges of analyzing count data and examining the factors associated with daily cigarette consumption among the young people in Turkey. We fitted Poisson (P), negative binomial (NB), zero-inflated Poisson (ZIP), zero-inflated negative binomial (ZINB), Poisson hurdle (PH) and negative binomial hurdle (NBH) regressions to cigarette consumption count data by using the 2014 Turkey Health Survey. Our results showed that the ZINB and NBH models should be preferred. We also found that, gender, employment and tobacco use at home are more effective factors for smokers and nonsmokers in the 15–24 age group in Turkey.     

Relation of infants' and mothers' pointing to infants' vocabulary measured directly and with parental reports

Infants' and parents' pointing gestures predict infants' concurrent and prospective language development. Most studies have measured vocabulary size using parental reports. However, parents tend to underestimate or overestimate infants' vocabulary necessitating the use of direct measures alongside parent reports. The present study examined whether mothers' index-finger pointing, and infants' whole-hand and index-finger pointing at 14 months associate with infants' receptive and expressive vocabulary based on parental reports and directly measured lexical processing efficiency (LPE) concurrently at 14 months and prospectively at 18 months. We used the decorated room paradigm to measure pointing frequency, the Turkish communicative development inventory I to measure infants' receptive vocabulary, Turkish communicative development inventory II to measure their expressive vocabulary, and the Looking-While-Listening (LWL) task to measure LPE. At 14 months, 34 mother-infant dyads, and at 18 months, 30 dyads were included in the analyses. We found that only infants' index-finger pointing frequency at 14 months predicted their LPE (both reaction time and accuracy) prospectively at 18 months but not concurrently at 14 months. Neither maternal pointing nor infants' pointing predicted their receptive and expressive vocabulary based on indirect measurement. The results extend the evidence on the relation between index-finger pointing and language development to a more direct measure of vocabulary.     

The relationship between vitamin D level and erectile dysfunction in patients with type 2 diabetes mellitus

Recent studies have suggested that a relationship could exist between 25-hydroxyvitamin D [25(OH)D] deficiency and erectile dysfunction (ED). The present study evaluated the relationship between 25(OH)D levels and ED in male patients with type 2 diabetes mellitus (DM). The study included 98 patients with type 2?DM aged between 18–80 years. The International Index of Erectile Function (IIEF-5) Questionnaire was administered. The patients were divided into three groups according to IIEF-5 scoring: IIEF-5 score between 5–10, severe ED; IIEF-5 score between 11–20, moderate ED; IIEF-5 score between 21–25, no ED. Biochemical parameters, 25(OH)D and hormonal analysis tests were obtained in all patients. All parameters were compared between these three groups. Of 98 patients included in the study, 32 had severe ED, 45 had moderate ED and 21 had no ED. The mean age was 55.12?±?9.39 years and the mean 25(OH)D level was 13.69?±?8.15?ng/ml. When the three groups were compared, 25(OH)D levels were significantly lower in patients with the IIEF-5 score between 5–10 (p?=?0.020). There was a moderate positive relationship between IIEF-5 score and 25(OH)D level (r?=?0.21, p?=?0.038). The patients with severe ED have considerably lower 25(OH)D levels.     

Interplay of gender subtext and local culture in the organizational logic: the case of a textile factory in Turkey

This paper examines gender as a constitutive element of inequality regimes in the workplace. The organizational logic of workplace is reproduced through accepted but unequal policies and principles. The organizational dynamics of the gendered workplace are embedded in the articulation of global and local markets. The article elaborates on the nature of the organizational logic by focusing on the local dynamics of a Central Anatolian city, Çorum, based on a case study conducted in Turkey. We observe how capitalist organizational logic and gender subtext operate in and through the conservative culture specific to this locality. Through the interactions between employers and employees, the engagement between the capitalist organization and gender subtext constructs the realities of workplace. Workers’ responses to the structural, cultural, interactional and identity dynamics of the organization are to be understood within the triangle of skill, care and honour in capitalist organizational logic. Embedded in all these responses is a specific emphasis on virtuous female worker. Such an ideal worker fits both the capitalist organizational logic and patriarchal system.     

Logistic Regression Analysis of the Outlook of People in Turkey Regarding the Principles of Secularism and Republic for the New Constitution to be Prepared

This paper studies demands and expectations of people about the content of the new constitution supposed to be prepared after the parliamentary election of June, 2011 in Turkey. For that purpose, a survey was applied across the country to 6,810 people with different ethnic identities, religious faiths and political tendencies. Economic and social conditions of the respondents were studied and subsequently their tendencies regarding two of the most frequently discussed topics of the country namely Secularism and Republic were explored. For that purpose, statistical technics and the logistic regression technic were used. We interestingly found out that the two principles mentioned above have been substantially accepted by different parts of the society and there are no considerable negative reactions regarding those issues. It was found out in this study that almost all parts of the Turkish society accept some fundamental principles of the regime like Republic and Secularism as well as the Presidency of Religious Affairs. It appears that in Turkey basic differences regarding perspectives on political and social values arise rather from sectarian identities.