Rate-optimal tests for jumps in diffusion processes

Suppose one has a sample of high-frequency intraday discrete observations of a continuous time random process, such as foreign exchange rates and stock prices, and wants to test for the presence of jumps in the process. We show that the power of any test of this hypothesis depends on the frequency of observation. In particular, if the process is observed at intervals of length $1/n$ 1 / n and the instantaneous volatility of the process is given by $ \sigma _{t}$ σ t , we show that at best one can detect jumps of height no smaller than $\sigma _{t}\sqrt{2\log (n)/n}$ σ t 2 log ( n ) / n . We present a new test which achieves this rate for diffusion-type processes, and examine its finite-sample properties using simulations.     

The General Expressions for the Moments of the Stochastic Shrinkage Parameters of the Liu Type Estimator

ABSTRACT

One of the problems with the Liu estimator is the appropriate value for the unknown biasing parameter d. In this article we consider the optimum value for d and give upper bound for the expected value of the estimator of this biasing parameter. We also derive the general expressions for the moments of the stochastic shrinkage parameters of the Liu estimator and the generalized Liu estimator. Numerical calculations are carried out to illustrate the behavior of the mean and variance of the biasing parameter. Also, a numerical example is given to illustrate the effect of the biasing parameter d, on the mean square error of the Liu estimator.     

On the characterization of maximum likelihood estimators for location-scale families

Given maximum likelihood equations for location and scale parameters, one determines conditions under which there exists a uniquely defined parametric statistical model, whose location and scale maximum likelihood estimators are the given ones. The constructive approach is exemplified at several kinds of mean estimators including the mean, mean square, mean mean and stretched power mean. The possible extension of the method to more general situations is discussed and illustrated at the sample median maximum likelihood estimator.     

The Relationship Between Psychological Understanding and Positive Social Behaviors

This research investigates the relationship between psychological understanding and positive social behavior in preschool children. A sample of 67 children were given measures of mental state understanding and emotion understanding. Positive social behavior was measured by classroom observation, teacher report and peer ratings. Both mental state understanding and emotion understanding were positively related to teacher ratings of social skills, behavioral observers’ global ratings of social skills and peer popularity. When language ability was partialled out of these relationships, many of the significant correlations disappeared; however, for variables related to peers’ perceptions, psychological understanding continued to predict unique variance. The results are discussed in terms of the multiple determinacy of positive social behaviors and the potential role of language in these processes.     

Clinicians' fallacies in psychiatric practice

Eleven common clinicians' fallacies have been briefly described. Based on experience, the authors of this article believe these are the most common and pernicious ones in interdisciplinary psychiatric treatment. These patterns may lead to erroneous interdisciplinary treatment decisions for many patients. In order to protect the well-being of psychiatric patients, their families, and the integrity of interdisciplinary treatment teams, it behooves each and every team member to become knowledgeable about clinicians' fallacies. Those aware of clinician's fallacies will reason more soundly basing judgments on empirical evidence, careful observation, measurement, and a determination not to be influenced by emotional appeals.     

Interpersonal distance and personal space: A conceptual and methodological note

Forty male and forty female subjects were led to anticipate an interaction in which they were to take control, or were to avoid being controlled by another. Both interpersonal distances and personal spaces were greater when subjects were avoiding another's control attempts. Thus, both distance and space expand reactively in response to a threat to control. In contrast to earlier research (Edney, Walker, & Jordan, 1976), we obtained no relationship between interpersonal distance and size of personal space. The pattern of results suggests that the curvilinear relationship obtained by Edney et al. was due largely to the instructions they gave subjects regarding distance and space.     

General affine transform families: why is the Pareto an exponential transform?

A slight extension of the transform method by Efron (1982) is used to analyze general affine transforms of arbitrary random variables. Our application concerns the simple question “Why is the Pareto an exponential transform?”. This result, already known to Gumbel (1958), finds a satisfactory mathematical answer in the framework of general affine transforms, and holds for several other distributions including heavy-tailed ones.     

Lay persons' emotional reactions toward an abused elderly person

This study examined lay persons' emotional reactions to abuse, with special attention to two types of disease: Alzheimer's disease and osteoporosis. A total of 169 adults (mean age = 60) were interviewed face-to-face using a vignette methodology. Although the majority of the participants found the vignette to describe a situation of abuse, one-quarter did not consider it an abusive situation. The person described in the vignette elicited more positive than negative emotions, with a high percentage of participants expressing sympathy, desire to help, and concern. The various emotional reactions to abuse are associated with different correlates.     

Risk-averse and risk-taking newsvendors: a conditional expected value approach

Introduction  We consider a company sourcing a product with short life cycle to stock using the framework of the newsvendor model. Traditionally, risk-neutral inventory managers are considered optimizing the expected cost or profit. But experimental findings state that the actual quantity ordered deviates from the optimal quantity derived from the classical newsvendor model. Model  Recently, the newsvendor model with objectives different from maximizing expected profit has been an active field of research. Here, we propose a newsvendor model where the inventory manager can control internal and customer-oriented performance measures. The objective function is a convex combination of conditional expected values of low and high profits, respectively. Results   We give a qualitative characterization of the optimal order quantity and the resulting performance measures in dependence of the model parameters. A risk-averse inventory manager cannot Pareto-dominate a risk-neutral or risk-taking inventory manager with respect to the expected profit and the level of product availability. Finally, the risk preferences of the inventory manager are expressed as a function of the profit value of the product with respect to the level of product availability and the probability of loss, respectively.      

Personality,Pentecostal ism,and Glossolalia: A Research Note on Some Unsuccessful Research*

L'auteur a d'abord tenté de mettre en rapport l'attrait des offices religieux d'une église de la Pentecôte et les résultats d'un test psychologique basé sur I'achévement de phrases incomplètes. II ne réussit àétablir aucune association entre les deux mesures. II tenta ensuite de mettre en relation les résultats obtenus dans un inventaire multidimen-sionnel de la personnalité, le M.M.P.I., et l‘évaluation de deux films: l'un décrivant un “revival” d'une église de la Pentecôte et l'autre, une réunion où Ton avait provoqué expérimentalement une manifestation du don des langues. A nouveau, aucune association statistique ne put être établie. L'auteur est néanmoins d'avis que la manifestation du don des langues produite expérimentalement offre suffisamment d'intérét pour en faire état dans le présent rapport de recherche.