Non-Normal Bivariate Distributions with Normal Marginals

The purpose of this note is to indicate that Fieller's Theorem can be expressed in the matrix formulation of the general linear model. The practical consequence is that one general computer program which can estimate the parameters and test the validity of a pertinent model, can also compute confidence limits for the ratios of any linear combinations of the parameters.     

Trend analysis with response incompatible formats and measurement error

The increasing popularity of longitudinal studies, along with the rapid advances in science and technology, has created a potential incompatibility between data formats, which leads to an inference problem when applying conventional statistical methods. This inference problem is further compounded by measurement error, since incompatible data format often arise in the context of measuring latent constructs. Without a systematic study of the impact of scale differences, ad-hoc approaches generally lead to inconsistent estimates and thus, invalid statistical inferences. In this paper, we examine the asymptotic properties and identify conditions that guarantee consistent estimation within the context of a trend analysis with response incompatible formats and measurement error. For model estimation, we introduce two competing methods that use a generalized estimating equation approach to provide inferences for the parameters of interest, and highlight the relative strengths of each method. The approach is illustrated by data obtained from a multi-centre AIDS cohort study (MACS), where a trend analysis of an immunologic marker of HIV infection is of interest.     

Occupational and industrial contextual indicators in income determination models for Australia

Contextual variables, such as average education, gender composition, ethnicity and unionization, influence individual incomes differently when aggregated to occupations and to industries. Discriminatory effects exerted on income by ethnic and gender segregation in occupational labor markets are in some cases counterbalanced by segregation in industrial labor markets. Employment in different industries influences income irrespective of individual characteristics of the employees and irrespective of aggregate characteristics of their occupations. This impact of industrial location is also independent of organizational characteristics of the industries, even if the choice of characteristics is determined by the economic segmentation theory.     

The time budget in socio-demographic statistics

The paper describes a Polish time budget survey conducted in 1976 on a rotation sample of the whole (non-agricultural and agricultural) adult population. Different time budget indicators are presented and their linkages with other statistical data and usefulness for social policy formulation and evaluation are discussed. Some new time indicators, not used in previous surveys, are recommended. Usefulness of time budged surveys for assessing an account of labor force and investigating of the social distribution of labor time as well as leisure time is underlined. The possibility of using time budget data for analyses of the social distribution of some welfare outlays in the field of cultural participation and consumption is also indicated. The paper is concerned with some methodological problems and the applicability of time budget research, rather than a comprehensive presentation of survey results.     

Demographic characteristics,work complexity and economic setting as social status determinants

Various aspects of social standing are significantly, though differently, determined by demographic characteristics, by employment in different economic sectors and industries, and by work complexity. Various sectors and industries influence differently status achievement, and are characterized by different configurations of status determinants of their workforces. The public (government) sector is more meritocratic than the private one, as far as income is concerned. Also, the male achievement pattern seems to be more meritocratic, while the female pattern is more sensitive to transient influences. The indicators of socio-economic status, occupational prestige and income reflect separate dimensions of social standing. The indicators of work complexity with data, people and things are good predictors of individual's social position.     

Modern variable selection for longitudinal semi-parametric models with missing data

Penalized methods for variable selection such as the Smoothly Clipped Absolute Deviation penalty have been increasingly applied to aid variable section in regression analysis. Much of the literature has focused on parametric models, while a few recent studies have shifted the focus and developed their applications for the popular semi-parametric, or distribution-free, generalized estimating equations (GEEs) and weighted GEE (WGEE). However, although the WGEE is composed of one main and one missing-data module, available methods only focus on the main module, with no variable selection for the missing-data module. In this paper, we develop a new approach to further extend the existing methods to enable variable selection for both modules. The approach is illustrated by both real and simulated study data.     

Amphibians in an urban environment: a case study from a central European city (Wrocław,Poland)

Urban Ecosystems - In 2016, we studied the occurrence of amphibians in 231 selected ponds in the city of Wroc?aw (Lower Silesia, Poland) and confirmed the occurrence of 10 species: Bombina...