A new class of distribution having decreasing,increasing, and bathtub-shaped failure rate

In this article, we propose a new class of distribution which is based on the concept of exponentiated generalization with some modification so as to provide a better result in terms of flexibility. Our proposed distribution accommodates various shapes of hazard rate including the bathtub. Exponential distribution has been taken as the baseline distribution. Various statistical properties of the proposed distribution have been studied. We have used the method of maximum likelihood for estimation of the parameters of the proposed model. Last, we have analyzed four real datasets to illustrate the flexibility of the model in comparison to eight existing well-known distributions.     

Categorical variable selection based on entropy reduction

This paper presents the derivation of a categorical variable selection technique which utilizes the entropy function as a measure of variability for nominally scaled variables. The selection criterion uses likelihood ratio statistics which, for the hypotheses under consideration, are identical to minimum discrimination information statistics. Thus, the paper provides an alternative motivation for a selection technique based on discriminatory power, and it provides an extension of that technique to the multipopulation discrimination problem. The selection technique is illustrated for a study in which we discriminate among three populations: cervical cancer patients, population-based controls, and hospital-based controls.     

A Note on the Moment Generating Function

A simple proof is given to show that there always exists a neighborhood of zero in which a moment generating function has a power series expansion. Thus, the relation between moments and derivatives of the moment generating function at zero can be obtained without resorting to postcalculus theorems.     

Discrete-time survival analysis under ranked set sampling: an application to Turkish motor insurance data

Survival models with continuous-time data are still superior methods of survival analysis. However when the survival data is discrete, taking it as continuous leads the researchers to incorrect results and interpretations. The discrete-time survival model has some advantages in applications such as it can be used for non-proportional hazards, time-varying covariates and tied observations. However, it has a disadvantage about the reconstruction of the survival data and working with big data sets. Actuaries are often rely on complex and big data whereas they have to be quick and efficient for short period analysis. Using the mass always creates inefficient processes and consumes time. Therefore sampling design becomes more and more important in order to get reliable results. In this study, we take into account sampling methods in discrete-time survival model using a real data set on motor insurance. To see the efficiency of the proposed methodology we conducted a simulation study.     

Dimensions of Risk Perception for Financial and Health Risks

This study of 29 MBA students compares two models of risk perception for both financial and health risk stimuli. The first, inspired by Luce and Weber's Conjoint Expected Risk (CER) model, uses five dimensions: probability of gain, loss and status quo, and expected benefit and harm. The second, inspired by the Sovic et al. psychometric model, employs seven dimensions: voluntariness, dread, control, knowledge, catastrophic potential, novelty, and equity. The CER-type model provided a better fit for most subjects and stimuli. Adding the psychological risk dimensions from the Slovic et al. model explained only modestly more variance. Relationships between the dimensions of the two models are described and the construction of a hybrid model explored.     

简论直觉顿悟的思维特征和形成基础

直觉顿悟是认识发展和科学创新的重要思维方式,文章从形式的简捷性、过程的不明确性、灵感闪现时的精神恍惚性以及直觉本质的非逻辑性、结论整体的过渡态性质等方面分析了直觉顿悟的思维特征。认识的直觉顿悟不是偶然的,其形成基础是实践积累的“潜知”元素和实践需要激活“潜知”元素的重新组合,也是人们长期专注和沉思某一问题而积累能量释放的结果。