On the sums of probability functions of order statistics

When a random vector is independent and identically distributed, we have expressed the sums of the marginal probability functions of the order statistics of the random vector in terms of the common marginal probability functions of the random vector. We have also derived the relationships between the sums of the joint probability functions of two order statistics of the random vector and the common marginal probability functions of the random vector.     

Central Limit Theorems for Reduced U‐Statistics Under Dependence and Their Usefulness

A reduced ‐statistic is a ‐statistic with its summands drawn from a restricted but balanced set of pairs. In this article, central limit theorems are derived for reduced ‐statistics under ‐mixing, which significantly extends the work of Brown & Kildea in various aspects. It will be shown and illustrated that reduced ‐statistics are quite useful in deriving test statistics in various nonparametric testing problems.     

Bayesian False Discovery Rate Wavelet Shrinkage: Theory and Applications

Statistical inference in the wavelet domain remains a vibrant area of contemporary statistical research because of desirable properties of wavelet representations and the need of scientific community to process, explore, and summarize massive data sets. Prime examples are biomedical, geophysical, and internet related data. We propose two new approaches to wavelet shrinkage/thresholding.

In the spirit of Efron and Tibshirani's recent work on local false discovery rate, we propose Bayesian Local False Discovery Rate (BLFDR), where the underlying model on wavelet coefficients does not assume known variances. This approach to wavelet shrinkage is shown to be connected with shrinkage based on Bayes factors. The second proposal, Bayesian False Discovery Rate (BaFDR), is based on ordering of posterior probabilities of hypotheses on true wavelets coefficients being null, in Bayesian testing of multiple hypotheses.

We demonstrate that both approaches result in competitive shrinkage methods by contrasting them to some popular shrinkage techniques.     

Treatments of non-metric variables in partial least squares and principal component analysis

This paper reviews various treatments of non-metric variables in partial least squares (PLS) and principal component analysis (PCA) algorithms. The performance of different treatments is compared in an extensive simulation study under several typical data generating processes and associated recommendations are made. Moreover, we find that PLS-based methods are to prefer in practice, since, independent of the data generating process, PLS performs either as good as PCA or significantly outperforms it. As an application of PLS and PCA algorithms with non-metric variables we consider construction of a wealth index to predict household expenditures. Consistent with our simulation study, we find that a PLS-based wealth index with dummy coding outperforms PCA-based ones.     

Testing for Stochastic Monotonicity

We propose a test of the hypothesis of stochastic monotonicity. This hypothesis is of interest in many applications in economics. Our test is based on the supremum of a rescaled U‐statistic. We show that its asymptotic distribution is Gumbel. The proof is difficult because the approximating Gaussian stochastic process contains both a stationary and a nonstationary part, and so we have to extend existing results that only apply to either one or the other case. We also propose a refinement to the asymptotic approximation that we show works much better in finite samples. We apply our test to the study of intergenerational income mobility.     

Group variable selection in cardiopulmonary cerebral resuscitation data for veterinary patients

Cardiopulmonary cerebral resuscitation (CPCR) is a procedure to restore spontaneous circulation in patients with cardiopulmonary arrest (CPA). While animals with CPA generally have a lower success rate of CPCR than people do, CPCR studies in veterinary patients have been limited. In this paper, we construct a model for predicting success or failure of CPCR, and identifying and evaluating factors that affect the success of CPCR in veterinary patients. Due to reparametrization using multiple dummy variables or close proximity in nature, many variables in the data form groups, and thus a desirable method should take this grouping feature into account in variable selection. To accomplish these goals, we propose an adaptive group bridge method for a logistic regression model. The performance of the proposed method is evaluated under different simulated setups and compared with several other regression methods. Using the logistic group bridge model, we analyze data from a CPCR study for veterinary patients and discuss their implications on the practice of veterinary medicine.     

Organizational Support in the Workplace: The Case of Korean Hospital Employees

This paper tests three hypotheses on who getsmore support from his or her work organization: (1) Thevalidation hypothesis predicts that employees withgreater social support from their co-workers and supervisors receive more organizationalsupport, because their support validates or legitimizesorganizational support; (2) the positive affectivityhypothesis predicts that employees high on positiveaffect receive more organizational support, becausethey are more likable; and (3) the moderation hypothesispredicts that positive affect and social support do notgenerate organizational support independently, but each acts on the other to affectorganizational support. An assessment of the hypothesesover a sample of 1882 hospital employees in Koreaprovided strong support for the validation hypothesisand partial support for the moderation hypothesis. Contraryto the positive affectivity hypothesis, employees' gooddisposition in itself works against the bringing forthof relevant organizational support, net of support from their supervisors and co-workers.Additional findings related to the unique features ofthe current hospital employees in Korea are alsoreported. Finally, we discuss cross-cultural research implications of the study in moredetail.     

The social,emotional, and behavioral skill antecedents to college students' volunteering during the COVID-19 pandemic

The disruptions to community functioning caused by the COVID-19 pandemic spurred individuals to action. This empirical study investigated the social, emotional, and behavioral (SEB) skill antecedents to college students' volunteering during the COVID-19 pandemic (N = 248, Mage = 20.6). We assessed eight SEB skills at the onset of a volunteering program, and students' volunteer hours were assessed 10-weeks later. Approximately 41.5% of the sample did not complete any volunteer hours. Higher levels of perspective taking skill, abstract thinking skill, and stress regulation were associated with more time spent volunteering. These results suggest that strength in particular SEB skills can prospectively predict prosocial civic behaviors.     

A Comparison of Sanctions in African American and White TANF Leavers

In this study the authors explore racial disparities in the uses of sanctions and the different impact of sanctions on the economic well-being of African American and White TANF leavers. The study analyzed 907 African American and 1,336 White welfare leavers from the 1999 and 2002 data of the NSAF. Chi-square results show that sanctions are more significantly imposed to African Americans than Whites. On the other hand, regression results show that the impact of sanctions on the employment and family income of African Americans and Whites are comparable. Implications suggest that states need to have an appropriate sanction process, training programs for caseworkers, or other policy changes to reduce the racial disparities.     

Older lesbian sexuality: identity, sexual behavior, and the impact of aging

In response to the very limited and mostly outdated literature on older lesbian sexuality, this exploratory study examined older lesbian sexual identity, romantic relationships, the impact of aging, and experiences of discrimination within these contexts. Utilizing an online survey that recruited via numerous online lesbian communities and snowball sampling, 456 lesbians over the age of 50 responded to closed, Likert scale, and open-ended questions that provided a preliminary understanding of older lesbian sexuality. The results indicated that older lesbians have experienced fluidity in past romantic and sexual relationships, as well as in erotic fantasies, despite strong identification with being lesbian. The findings also indicate a decreased focus on sexuality in the context of relationships, with more focus on stability and continuity. Future research is needed that provides greater specificity and detail about older lesbian conceptions of sexual behavior and sexual identity labels, as well as specific sexual behaviors.