Precedence probabilities and their applications

In precedence tests, the test powers are given by the probabilities P(Y_(i) > X_(j)) for some i and j, where X_(j) and Y_(i) are the order statistics of two independent random samples. Such probabilities can also arise in reliability theory. In this paper, we investigate the properties of these probabilities and their applications.     

Integrating psychometric and cultural theory approaches to formulate an alternative measure of risk perception

Psychometric and cultural theory are key approaches used to explain risk perceptions. However, both approaches explain only 20 and 5–10% of the variance of risk perceptions, respectively. Through advances in social psychology, terror management theory revealed that certain survey questions used in the psychometric approach primed thoughts of death. Such unintentional priming evoked defense mechanisms that would subconsciously activate participants’ cultural biases and values when answering some questions but not others. There are two implications: one, psychometric theorists need to modify their questionnaires to reduce the incidence of priming thoughts of death; and two, integrating the psychometric and cultural theory approaches may potentially explain a higher amount of variance in risk perceptions. Specifically, attitudes (psychometric approach), demographics, affect and past behavior collectively influence cultural biases, which in turn exert an effect on risk perception. However, such a model calls for an appropriate measure of the dynamic nature of cultural biases that current attitudinal measures fall short of. Drawing from methodology within industrial/organizational psychology, the Situational Judgment Test (SJT) is proposed as an alternative measure for risk perception. Steps to designing an SJT are outlined and followed through to culminate in a 10-item SJT that measures cultural biases.     

The peculiar shrinkage properties of partial least squares regression

Partial least squares regression has been widely adopted within some areas as a useful alternative to ordinary least squares regression in the manner of other shrinkage methods such as principal components regression and ridge regression. In this paper we examine the nature of this shrinkage and demonstrate that partial least squares regression exhibits some undesirable properties.     

An EOQ inventory model for items with Weibull distribution deterioration,ramp type demand rate and partial backlogging

In this paper, an EOQ inventory model is presented depleted not only by demand but also by Weibull distribution deterioration, in which the demand rate is assumed that with a ramp type function of time. In the model, shortages are allowed partial backlogging and the backlogging rate is variable and is dependent on waiting time for the next replenishment. The method is illustrated by three numerical examples, and sensitivity analysis of the optimal solution with respect to parameters of the system is carried out.     

Maximizing a Family of Optimal Statistics over a Nuisance Parameter with Applications to Genetic Data Analysis

In this article, a simple algorithm is used to maximize a family of optimal statistics for hypothesis testing with a nuisance parameter not defined under the null hypothesis. This arises from genetic linkage and association studies and other hypothesis testing problems. The maximum of optimal statistics over the nuisance parameter space can be used as a robust test in this situation. Here, we use the maximum and minimum statistics to examine the sensitivity of testing results with respect to the unknown nuisance parameter. Examples from genetic linkage analysis using affected sub pairs and a candidate-gene association study in case-parents trio design are studied.     

Testing for Circular Reflective Symmetry about a Known Median Axis

Circular data arise in many contexts, a particularly rich source being animal orientation experiments. Often, in the analysis of such data, a fundamental question of scientific interest is whether the underlying distribution is reflectively symmetric about some specific axis. In this paper, the situation in which the axis of interest is known to be a median axis is considered and a simple, asymptotically distribution- free test for circular reflective symmetry against skew alternatives is developed. The results from a simulation study lead to a testing strategy incorporating the new test and the circular analogue of the modified runs test of Modarres & Gastwirth (1996). The application of the testing strategy is illustrated using circular data arising from two animal orientation experiments.     

Pooling multivariate data under W, LR and LM tests

Two independent random samples are drawn from two multivariate normal populations with mean vectors μ1 and μ2 and a common variance-covariance matrix Σ. Ahmed and Saleh (1990) considered preliminary test maximum likelihood estimator (PMLTE) for estimating μ1 based on the Hotelling's T _N ², when it is suspected that μ1=μ2. In this paper, the PTMLE based on the Wald (W), Likelihood Ratio (LR) and Lagrangian Multiplier (LM) tests are considered. Using the quadratic risk function, the conditions of superiority of the proposed estimator for departure parameter are derived. A max-min rule for the size of the preliminary test of significance is presented. It is demonstrated that the PTMLE based on W test produces the highest minimum guaranteed efficiencies compared to UMLE among the three test procedures.     

On a test for structural stability of euler conditions parameters estimated via the generalized method of moments estimator: small sample properties

This paper presents Monte Carlo experiments on the small sample performance of the predictive test for structural change proposed by Ghysels and Hall. The predictive test was found to be more powerful than the overidentifying restrictions test in terms of size-corrected power when a shift in parameter has occurred. Also, it was found that the power of the predictive test decreases drastically as the number of the out-sample data decreases.     

试析短跑放松技术的理论方法及检测

文章从生理学的角度,阐述了放松技术对提高短跑成绩的作用,认为放松技术主要指肌 肉放松。肌肉放松可增大肌肉的收缩力量和收缩速度,提高速度耐力和肌肉、关节的灵活性及柔 韧性。同时,从心理学的角度分析了短跑运动员的情绪、意志、自信心和竞争力等心理品质对肌 肉放松的影响,结合训练实践,针对性的提出了短跑放松训练方法和检测手段。     

Saddlepoint approximations for some models of circular data

In this article we provide saddlepoint approximations for some important models of circular data. The particularity of these saddlepoint approximations is that they do not require solving the saddlepoint equation iteratively, so their evaluation is immediate. We first give very accurate approximations to P-values, critical values and power functions for some optimal tests regarding the concentration parameter under wrapped symmetric α-stable and circular normal models. Then, we consider an approximation to the distribution of a projection of the two-dimensional Pearson random walk with exponential step sizes.