Restricted Two Parameter Ridge Estimator

In 2005 Lipovetsky and Conklin proposed an estimator, the two parameter ridge estimator (TRE), as an alternative to the ordinary least squares estimator (OLSE) and the ordinary ridge estimator (RE) in the presence of multicollinearity, and in 2006 Lipovetsky improved the two parameter model. In this paper, we introduce two new estimators, one of which is the modified two parameter ridge estimator (MTRE) defined by following Swindel's paper of 1976. The other one is the restricted two parameter ridge estimator (RTRE) which is derived by setting additional linear restrictions on the parameter vectors. This estimator is a generalization of the restricted least squares estimator (RLSE) and includes the restricted ridge estimator (RRE) proposed by Groß in 2003. A numerical example is provided and a simulation study is conducted for the comparisons of the RTRE with the OLSE, RLSE, RE, RRE and TRE.     

The effects of the proxy information on the iterative Stein-rule estimator of the disturbance variance

In a regression model with proxy variables, we consider the iterative estimator of the disturbance variance to obtain more precise estimates. In the formula of the estimator of the disturbance variance, the estimator is obtained by using Stein-rule (SR) estimator instead of OLS (ordinary least squares) estimator is called Iterative estimator of the disturbance variance. It is shown that, in a regression model with proxy variables the mean square error (MSE) of the iterative estimator of the disturbance variance is greater than the MSE of the disturbance variance related to the OLS estimator under certain conditions.     

A General Statistical Framework for Multistage Designs

Abstract. The efficiency of observational studies may be increased by applying multistage sampling designs. It is, however, not always transparent how to construct such a design to obtain increased efficiency. We here present a general statistical framework for describing and constructing multistage designs. We also provide tools for efficiency and cost‐efficiency comparisons, to facilitate the choice of sampling scheme. The comparisons are based on Fisher information matrices and the results are presented in graphs, where either efficiency or cost‐adjusted efficiency is plotted against a normalized measure of cost. The former curve resides in the unit square and is analogous to the receiver operating characteristic curve used for testing.     

Attachment Styles and Self‐Image in Turkish Adolescents

The purpose of this article is to examine the attachment styles and the relation of these styles to the self‐image in Turkish adolescents. The study included 378 adolescents (196 females and 182 males) from high schools with different socioeconomic status (SES) who were administered Relationship Scale Questionnaires and Offer Self‐Image Questionnaires. The findings indicate that adolescents from a low SES had significantly low scores on self‐image scales compared with those from high and middle SES. It was found that secure attachment patterns affect social relationships and superior adjustment aspects of self‐image positively. The results of this study show that attachment patterns play an important role in the development of the self‐image, which is a crucial psychological structure gained in adolescence.     

Collaboration in EU Framework Programmes – the case of the social sciences and humanities

The impact of the European Framework Programme (hereafter FP) projects is usually measured with reference to the possibilities offered for collaboration. In this research note we take a different perspective and explore the extent to which FPs have influenced the traditional performance of researchers and vice versa. The population reference for our study consists of the projects funded within the EU Sixth Framework Programme (FP6) between 2002 and 2006. Here, we have concentrated our analysis on the priority area of “citizens and governance in a knowledge-based society” (CIT).     

Difficulties in Diagnosing Sexual Abuse in Children with Condyloma Acuminata in Turkey

Human papillomavirus is responsible for anogenital warts and could be regarded as an indicator of possible sexual abuse in children. A genital wart was detected during an investigation of anti–hepatitis C virus positivity in a four-year-old male patient. No pathological findings of another sexually transmitted disease were found except complete cleft palate and circumferential lesions in the perianal region. No family member was anti-hepatitis C virus positive, but the patient's uncle and his wife had genital condylomata. Although detailed physical examination uncovered no other findings indicative of sexual abuse, suspicion of abuse could not be eliminated. Therefore, we wanted to draw the attention of health professionals to the association of anogenital warts and sexual abuse.     

Life satisfaction: A study based on the organization of personal projects

A methodology about personal project was used to understand perceived life satisfaction. Variables derived from the Personal Project Matrix were shown to explain variability in reported life satisfaction in two separate studies (university and professional samples). The results indicated that personal projects of students had been organized in systems and these systems' properties had meaningful effects on life satisfaction. A cross-validation analysis revealed that professionals' projects did not show the same systemic feature which students' projects had. But some variables such as projects performed in general places, stress, and amount of reported obstacles discriminated life satisfaction scores meaningfully.     

SATISFICING AND PRIOR‐FREE OPTIMALITY IN PRICE COMPETITION

We apply a model of satisficing to oligopoly markets with price competition. Sellers have profit aspirations reflecting their conjectures about their competitors' behavior and search for a price guaranteeing these aspirations. Because it seems implausible that people have detailed priors on the others' actions, we postulate that sellers entertain multiple conjectures to which no probabilities can be assigned. This allows us to propose a theory of “prior‐free” optimality and to examine experimentally whether people comply with it. We find that decision makers have difficulties in making prior‐free optimal choices. Most are content to just satisfice, although ways to aspire to more ambitious profits were obviously available. (JEL C92, C72, D43)     

Comparison of the Iterative Stein-Rule and the Usual Estimators of the Disturbance Variance Under the Pitman Nearness Criterion in a Linear Regression Model with Proxy Variables

In a linear regression model with proxy variables, the iterative Stein-rule estimator and the usual estimator of the disturbance variance is compared under the Pitman Nearness Criterion. The exact expression of Pitman Nearness probability is derived and numerically evaluated.     

ASYMPTOTIC NORMALITY OF GOODNESS-OF-FIT STATISTICS FOR SPARSE POISSON DATA

Goodness-of-fit tests for discrete data and models with parameters to be estimated are usually based on Pearson's χ2 or the Likelihood Ratio Statistic. Both are included in the family of Power-Divergence Statistics SDλ which are asymptotically χ2 distributed for the usual sampling schemes. We derive a limiting standard normal distribution for a standardization Tλ of SDλ under Poisson sampling by considering an approach with an increasing number of cells. In contrast to the χ2 asymptotics we do not require an increase of all expected values and thus meet the situation when data are sparse. Our limit result is useful even if a bootstrap test is used, because it implies that the statistic Tλ should be bootstrapped and not the sum SDλ. The peculiarity of our approach is that the models under test only specify associations. Hence we have to deal with an infinite number of nuisance parameters. We illustrate our approach with an application.