Conditions of Slope-Rotatability for Third-Order Polynomial Regression Models

In experimental design for response surface analysis, it is sometimes of interest to estimate the difference of responses at two points. If differences at points close together are involved, the design that reliably estimates the slope of the response surface is important. In particular, Hader and Park (1978 Hader , R. J. , Park , S. H. ( 1978 ). Slope-rotatable central composite designs . Technometrics 20 : 413 – 417 .[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]) suggested the concept of slope-rotatability and studied slope rotatable central composite designs. Until now, many response surface designs including central composite designs have been suggested for fitting second order response surface models. However, we often need to fit third-order polynomial regression models. In this article, we suggest extended central composite designs (ECCDs) to fit third-order models and find the necessary and sufficient conditions for slope-rotatability over all directions in the third-order polynomial models.     

A Comparison of Spatiotemporal Surveillance Methods for Nonhomogeneous Change Size

Spatiotemporal surveillance, especially in detection of emerging outbreaks is of particular importance. When an outbreak spreads across some areas, the incidence rate at the center of the outbreak area might be expected to be much higher than the rate at its edge. However, to the best of our knowledge, all existing methods assume a uniformly increasing rate across the entire area of the outbreak. The purpose of this study is to compare the performance of the spatiotemporal surveillance methods such as multivariate cumulative sum (MCUSUM) or multivariate exponentially weighted moving average (MEWMA) when the changes in size are nonhomogeneous. Monte Carlo simulations were conducted to examine the properties of these spatiotemporal surveillance methods and compared them in terms of the detection speed and the identification rate under various scenarios. The results showed that when nonhomogeneous change sizes are involved, the MCUSUM method taking into account spatial nonhomogeneity of increase rates yields a better identification than the method ignoring such change size pattern although the detection speeds are similar. Further, a case study for the detection of male thyroid cancer data in New Mexico in the United States was performed to demonstrate the applicability of these methods.     

Toward an Understanding of the Influence of Cultural Background and Domain Experience on the Effects of Risk‐Pricing Formats on Risk Perception

Risk‐information framing can be a powerful tool for aiding the communication of risk and improving decision making. However, little work has investigated the extent that these framing effects depend on the characteristics of the perceiver. In our study, we examine whether the effects of different risk‐pricing formats on risky choices are the same for all individuals, no matter their domain experience or cultural background, or whether there are interactions between these factors. Survey 1 revealed that three risk‐pricing formats of the same choice problem resulted in the same individuals making different risky choices (preference reversal), suggesting that risk perception was distorted by the risk‐pricing format manipulation. In Survey 2, the effects of the risk‐pricing formats were shown to differ by the participants’ cultural background (Asian vs. European) and the extent of their domain experience. The fact that there were no differences between the cultural or domain experience groups in their overall tendency to select riskier (cf. safer) choices indicates that risk behavior differences between groups are often closely linked to perceptual, rather than simply attitudinal, cognitive processes. The results demonstrate the complex, interactive cognitive processes that are used to encode risk information, involving the framing of the information and the cultural background and previous experiences of the individual. We conclude that it is important to consider the characteristics of the individual (e.g., culture, domain experience, etc.) when manipulating risk‐information framing with the aim of improving risk communication.     

Prevalence of Sexual Dysfunction and Associated Risk Factors in Middle-Aged and Elderly Korean Men in Primary Care

Although several studies have individually investigated the risk factors for erectile dysfunction (ED), premature ejaculation (PE), and late-onset hypogonadism (LOH), few studies have considered ED, PE, and LOH as categories of sexual dysfunction (SD) within the same population. We therefore aimed to investigate the prevalence of SD and its associated risk factors among men in primary care. Study participants were enrolled by 18 family physicians from 15 hospital-based family practices in Korea between August 2010 and May 2011. Participants answered a questionnaire regarding their demographic characteristics and lifestyle factors as well as the Korean versions of the Androgen Deficiency in the Aging Male, the International Index of Erectile Function, and the Premature Ejaculation Diagnostic Tool questionnaires. SD prevalence was 64.9% among study participants who were ≥ 40 years of age. ED prevalence was 43.7%, PE prevalence was 38.6%, and LOH prevalence was 16.8%. SD prevalence was significantly associated with increased age, overweight, hypertension, diabetes, and depression. These findings highlight the importance of screening questions for SD in primary care, especially among older male patients with the identified risk factors.     

Youth–Family,Youth–School Relationship,and Depression

This study sought to examine the association between adolescents’ relationship with family and school and depressive symptoms across ethnic/racial groups (White, Black, Hispanic, and Asian), and to test potentially unique explanatory power in youth–family relationship versus youth–school relationship, in a sample of 4,783 adolescents. Depressive symptoms were assessed with a 19-item, modified Center for Epidemiologic Studies-Depression Scale (CES-D). The results indicated that youth–family relationship and youth–school relationship were significant predictors of adolescent depression. However, the findings of the study indicated that unique contributions by youth–family relationship and youth–school relationship were different by racial/ethnic groups. These findings elucidate protective factors for adolescent depression and highlight the importance of cultural context of each racial/ethnic group.     

The Dynamics of Age and Sex in the Development of Mother–Infant Vocal Communication Between 3 and 11 Months

We followed the nondistressed vocalization dynamics of 30 mother–infant dyads observed in a naturalistic setting using multiple time points between 3 and 11 months to identify subtle relationships between age, sex and maternal behavior ending by 1 year of age with diverging trajectories of nondistressed vocalization. We observed no mean differences between boys and girls in frequency or duration of nondistressed vocalizations at any one time period. However, while these parameters were essentially static for boys, girls showed a quadratic developmental curve, declining in frequency and duration between 6 and 8 months and climbing above their early starting point by 9–11 months. Mothers of boys showed a linear decrease in the duration of their speech over the 9 months of our study. In contrast, mothers of girls showed quadratic patterns of ultimately increasing vocalization frequency and duration, over the months 3–11 of development. Finally, boys' and girls' vocalization contingent to maternal speech revealed no differences. Mothers of boys, however, did not change significantly over time, while mothers of girls showed an increase in contingent responsiveness from 3–5 months to 9–11 months and from 6–8 months to 9–11 months. A similar pattern was followed for object‐related maternal vocal responses.     

Simultaneous variable selection and outlier identification in linear regression using the mean-shift outlier model

We provide a method for simultaneous variable selection and outlier identification using the mean-shift outlier model. The procedure consists of two steps: the first step is to identify potential outliers, and the second step is to perform all possible subset regressions for the mean-shift outlier model containing the potential outliers identified in step 1. This procedure is helpful for model selection while simultaneously considering outlier identification, and can be used to identify multiple outliers. In addition, we can evaluate the impact on the regression model of simultaneous omission of variables and interesting observations. In an example, we provide detailed output from the R system, and compare the results with those using posterior model probabilities as proposed by Hoeting et al. [Comput. Stat. Data Anal. 22 (1996), pp. 252-270] for simultaneous variable selection and outlier identification.     

Complete convergence for weighted sums of negatively dependent random variables

In this paper, we obtain a complete convergence result for weighted sums of negatively dependent random variables under mild conditions of weights. This result generalizes and improves the result of Zarei and Jabbari (Stat Papers doi:, 2009). Our result also extends the result of Taylor et al. (Stoch Anal Appl 20:643–656, 2002) on unweighted average to a weighted average.