Generalized additive models for location, scale and shape

Summary.  A general class of statistical models for a univariate response variable is presented which we call the generalized additive model for location, scale and shape (GAMLSS). The model assumes independent observations of the response variable y given the parameters, the explanatory variables and the values of the random effects. The distribution for the response variable in the GAMLSS can be selected from a very general family of distributions including highly skew or kurtotic continuous and discrete distributions. The systematic part of the model is expanded to allow modelling not only of the mean (or location) but also of the other parameters of the distribution of y , as parametric and/or additive nonparametric (smooth) functions of explanatory variables and/or random-effects terms. Maximum (penalized) likelihood estimation is used to fit the (non)parametric models. A Newton–Raphson or Fisher scoring algorithm is used to maximize the (penalized) likelihood. The additive terms in the model are fitted by using a backfitting algorithm. Censored data are easily incorporated into the framework. Five data sets from different fields of application are analysed to emphasize the generality of the GAMLSS class of models.     

谈谈学分制下如何做好学生党建工作

全面推行学分制是高校教学改革的深化,是教育和教学改革的一个发展阶段.但由于学分制所带来的思想教育、学生党建等新情况、新问题,应值得所有教育者认真思考和研究的.本文围绕学分制实行后给学生党建工作带来的"四难"以及如何应对提出了一些理论和实践的思考.     

论宗教对我国西北边疆安全的双重影响

宗教对国家安全和社会政治稳定所产生的影响主要表现在其所特有的功能上。一方面,当宗教与社会政治体系相一致时,它就能促使其社会成员共同意志、共同信念的形成,对国家安全和社会政治稳定起到明显的促进作用;另一方面,宗教作为一种文化现象,还是科学与非科学、理性与非理性、道德与非道德相对而言的复杂统一体,因此具有滞后性、敏感性、触发性,当它成为引发社会不稳定的"互动源"和"感染源"时,会对国家安全和社会政治稳定产生负面影响。     

Modelling skewness and kurtosis with the BCPE density in GAMLSS

This paper illustrates the power of modern statistical modelling in understanding processes characterised by data that are skewed and have heavy tails. Our particular substantive problem concerns film box-office revenues. We are able to show that traditional modelling techniques based on the Pareto–Levy–Mandelbrot distribution led to what is actually a poorly supported conclusion that these data have infinite variance. This in turn led to the dominant paradigm of the movie business that ‘nobody knows anything’ and hence that box-office revenues cannot be predicted. Using the Box–Cox power exponential distribution within the generalized additive models for location, scale and shape framework, we are able to model box-office revenues and develop probabilistic statements about revenues.     

Investigating Heterogeneity in the Characterization of Risks Using Best Worst Scaling

This research proposes and implements a new approach to the elicitation and analysis of perceptions of risk. We use best worst scaling (BWS) to elicit the levels of control respondents believe they have over risks and the level of concern those risks prompt. The approach seeks perceptions of control and concern over a large risk set and the elicitation method is structured so as to reduce the cognitive burden typically associated with ranking over large sets. The BWS approach is designed to yield strong discrimination over items. Further, the approach permits derivation of individual‐level values, in this case of perceptions of control and worry, and analysis of how these vary over observable characteristics, through estimation of random parameter logit models. The approach is implemented for a set of 20 food and nonfood risks. The results show considerable heterogeneity in perceptions of control and worry, that the degree of heterogeneity varies across the risks, and that women systematically consider themselves to have less control over the risks than men.