A Primer on Visualizations for Comparing Populations,Including the Issue of Overlapping Confidence Intervals

In comparing a collection of K populations, it is common practice to display in one visualization confidence intervals for the corresponding population parameters θ₁, θ₂, …, θ_K. For a pair of confidence intervals that do (or do not) overlap, viewers of the visualization are cognitively compelled to declare that there is not (or there is) a statistically significant difference between the two corresponding population parameters. It is generally well known that the method of examining overlap of pairs of confidence intervals should not be used for formal hypothesis testing. However, use of a single visualization with overlapping and nonoverlapping confidence intervals leads many to draw such conclusions, despite the best efforts of statisticians toward preventing users from reaching such conclusions. In this article, we summarize some alternative visualizations from the literature that can be used to properly test equality between a pair of population parameters. We recommend that these visualizations be used with caution to avoid incorrect statistical inference. The methods presented require only that we have K sample estimates and their associated standard errors. We also assume that the sample estimators are independent, unbiased, and normally distributed.     

面向技术安全的机械设计数据库

机械设计中的计算机辅助设计和数据库技术对于技术安全工作正变得越来越重要，它需要CAD系统直接定位于一些特殊类型的机械。本文对数据库技术及设计结果作了介绍。     

Effects of human-related disturbance on breeding success of urban and non-urban blue tits (<Emphasis Type="Italic">Cyanistes caeruleus</Emphasis>)

There is a need to study the effects of urbanization on wildlife in order to understand the ecological implications of increasing urbanization and find out how to reduce its threats to biodiversity. The blue tit evolved as a forest species and prefers deciduous and mixed forests, whereas its nesting in urban habitats is a more recent phenomenon. Our long-term study of blue tit populations has been conducted in two habitats: an urban parkland (frequently visited by people) and a deciduous forest outside of the city. Using linear mixed modeling, we revealed that a relationship of blue tit breeding success (and the number of fledglings) with thermal conditions in May differed between the urban parkland and the forest. While the relationship was positive in the forest, it was negative in the parkland. In addition, breeding success in the parkland increased with increasing number of rainy days in May. We argue that the main possible reason for such patterns is human activity in the parkland, which interferes with tit parental care, especially the regular feeding of nestlings, whereas it is evidently associated with weather conditions. Human disturbance in the forest is likely to be negligible.     

Application of the Rural Development Index to Analysis of Rural Regions in Poland and Slovakia

The main purpose of this research was to construct a multi-dimensional (composite) index measuring the overall level of rural development and quality of life in individual rural regions of a given EU country. In the Rural Development Index (RDI) the rural development domains are represented by hundreds of partial socio-economic, environmental, infrastructural and administrative indicators/variables at NUTS-4 level (e.g. 991 variables/indicators describing various aspects of rural development in Poland; 340 variables/indicators in Slovakia). The weights of economic, social and environmental domains entering the RDI index are derived empirically from the econometrically estimated intra- and inter-regional migration function after selecting the “best” model from various alternative model specifications (e.g. panel estimate logistic regression nested error structure model, spatial effect models, etc.). The RDI is empirically applied to analysis of the main determinants of rural/regional development in individual rural areas in years 2002–2005 in Poland and Slovakia at NUTS-4 level. Due to its comprehensiveness the RDI Index is suitable both to analysis of the overall level of development of rural areas and to an evaluation of the impacts (impact indicator) of RD and structural programmes at regional levels (NUTS 2–5).     

设计过程中的工程数据库

本文从创造性设计过程的诸多方面叙述了建立工程数据库的重要性，指出了由于工程数据格式的不同，给数据通信带来的困难及解决办法。     

SOCIAL AND FAMILIAL ASPECTS OF ATTEMPTED AND COMPLETED SUICIDE OF YOUNG PEOPLE IN VICTORIA

A prospective study of youth suicide was carried out to determine the causes of the dramatic increase of suicide rates in males 15 to 25 years of age. Comprehensive information was collected through coronial enquiries on all 148 cases of completed youth suicide in Victoria during a 16 month period. Similar data were obtained through in-depth interviews of 105 hospitalised and 101 non-hospitalised attempters. In this paper only social and familial aspects of youth suicide are covered. Whilst the family setting of youth who attempted or completed suicide was similar to that of the general population, a higher proportion were homeless or living alone. Contrary to common assumptions, family relationships were much closer among completed than among attempted suicides. The unemployment rates were not higher than in all young people, and few subjects named unemployment as cause, but a relatively high number of them were neither studying nor looking for work. A high proportion of those who completed suicide had prior contact with the police. In conclusion, social factors do not significantly affect suicidal behaviour in young people.