New critical region tables for Fisher's exact test

The best-known non-asymptotic method for comparing two independent proportions is Fisher's exact text. The usual critical region (CR) tables for this test contain one or more of the following defects:they distinguish between rows and columns; they distinguish between the alternatives H = p1 < p2 and H = p1 > p2; they assume that the error for the two-tailed test is twice that of the one-tailed test; they do not use the optimal version of the test; they do not give both CRs for one and two tails at the same time. All this results in the unnecessary duplication of the space required for the tables, the construction of tables of low-powered methods, or the need to manipulate two different tables (one for the one-tailed test, the other for the two-tailed test). This paper presents CR tables which have been obtained from the most powerful version of Fisher's exact test and which occupy the minimum space possible. The tables, which are valid for one- or two-tailed tests, have levels of significance of 10%, 5% and 1% and values for N (the total size of both samples) of less than or equal to 40. This article shows how to calculate the P value in a specific problem, using the tables as a means of partial checking and as a preliminary step to determining the exact P value.     

A new approach to truncated regression for count data

AStA Advances in Statistical Analysis - Standard Poisson and negative binomial truncated regression models for count data include the regressors in the mean of the non-truncated distribution. In...     

Efficient generation of random vectors by using the ratio-of-uniforms method with ellipsoidal envelopes

Stochastic simulation is widely used to validate procedures and provide guidance for both theoretical and practical problems. Random variate generation is the basis of stochastic simulation. Applying the ratio-of-uniforms method to generate random vectors requires the ability to generate points uniformly in a suitable region of the space. Starting from the observation that, for many multivariate distributions, the multidimensional objective region can be covered by a hyper-ellipsoid more tightly than by a hyper-rectangle, a new algorithm to generate from multivariate distributions is proposed. Due to the computational saving it can produce, this method becomes an appealing statistical tool to generate random vectors from families of standard and nonstandard multivariate distributions. It is particularly interesting to generate from densities known up to a multiplicative constant, for example, from those arising in Bayesian computation. The proposed method is applied and its efficiency is shown for some classes of distributions.     

Exact Goodness‐of‐Fit Testing for the Ising Model

The Ising model is one of the simplest and most famous models of interacting systems. It was originally proposed to model ferromagnetic interactions in statistical physics and is now widely used to model spatial processes in many areas such as ecology, sociology, and genetics, usually without testing its goodness of fit. Here, we propose various test statistics and an exact goodness‐of‐fit test for the finite‐lattice Ising model. The theory of Markov bases has been developed in algebraic statistics for exact goodness‐of‐fit testing using a Monte Carlo approach. However, finding a Markov basis is often computationally intractable. Thus, we develop a Monte Carlo method for exact goodness‐of‐fit testing for the Ising model that avoids computing a Markov basis and also leads to a better connectivity of the Markov chain and hence to a faster convergence. We show how this method can be applied to analyze the spatial organization of receptors on the cell membrane.     

Influence of form and timing of social support on parental outcomes of a child-maltreatment prevention program

This study examines how the form of social support (informal or formal) and the time frame at which it is provided (at the start or end of the program) influence parental outcomes on the “Apoyo Personal y Familiar” (APF) program for at-risk families showing inadequate child-rearing practices. A total of 496 parents participated, 247 parents referred by the municipal social services in the Autonomous Community of Castile and Leon (Spain), and 249 non-referred parents. Initial and final levels of use of and satisfaction with informal and formal support were used as predictors of change scores in self-rating measures of beliefs about child development, perceptions of the parental role and child-rearing practices, applying hierarchical linear regression analyses. Perceived use of and satisfaction with support explained around 22% to 49% of the change scores in the Nurturist belief as a simple view of child development, Couple agreement on educational matters, Permissive–neglectful practices and Coercion practices, after accounting for the variance due to risk status, financial situation and family structure variables. Informal support always has a positive impact irrespective of when the help is provided, whereas formal support only has a positive impact when applied at the start of the program. The adequate provision of social supports can be an efficient way to prevent child maltreatment by promoting changes in parental beliefs and practices related to at-risk parenting.     

Participation in LGBTQ Organizations in Colombia: Motivations and Impacts

Studies on sexual minorities have shown the positive impact of the lesbian, gay, bisexual, trans, or queer (LGBTQ) community on the well-being of individuals. Few studies, however, have been interested in the role that LGBTQ organizations specifically play. Using a qualitative approach, this article examines individuals’ motivations to participate in LGBTQ organizations and how they think such participation impacts their lives. Semi-structured interviews were conducted with 20 self-identified LGBTQ adults living in the Andean region of Colombia. Thematic analysis with inductive coding was used, and six themes were identified. Within these, two findings are particularly relevant to the existing literature. First, organizations play an important role as educational spaces where individuals can learn about their sexual identity. Second, organizations can also impact families of origin by promoting a better understanding and acceptance of participants’ sexual identity, and by promoting solidarity with LGBTQ community members.     

Food Well-Being in Older Adults: Effects of a Universal Non-contributory Pension in Mexico

Social Indicators Research - One of the few universal programs in Latin America is the Food Pension for Adults Older than 68 (PAAM) of Mexico City, which aims to reduce food insecurity while...     

Collinearity diagnostic applied in ridge estimation through the variance inflation factor

The variance inflation factor (VIF) is used to detect the presence of linear relationships between two or more independent variables (i.e. collinearity) in the multiple linear regression model. However, the traditionally used VIF definitions encounter some problems when extended to the case of the ridge estimation (RE). This paper presents an extension of the VIF in RE by providing two alternative VIF expressions that overcome these problems in the general case. Some characteristics of these expressions are also presented and compared with the traditional expression. The results are illustrated with an economic example in the case of three independent variables and with a Monte Carlo simulation for the general case.     

Max–min optimal discriminating designs for several statistical models

In the literature, different optimality criteria have been considered for model identification. Most of the proposals assume the normal distribution for the response variable and thus they provide optimality criteria for discriminating between regression models. In this paper, a max–min approach is followed to discriminate among competing statistical models (i.e., probability distribution families). More specifically, k different statistical models (plausible for the data) are embedded in a more general model, which includes them as particular cases. The proposed optimal design maximizes the minimum KL-efficiency to discriminate between each rival model and the extended one. An equivalence theorem is proved and an algorithm is derived from it, which is useful to compute max–min KL-efficiency designs. Finally, the algorithm is run on two illustrative examples.     

Emotional labour and emotional exhaustion: Interpersonal and intrapersonal mechanisms

Abstract

In some occupations, particularly in the service sector, dealing with patients or clients may require an employee to pretend to have emotions that they do not really have, or to actually experience required emotions. The regulation of emotion can be either automatic or controlled. This study extends research on the consequences and processes of emotional labour in two ways. First, it examines how the use of different emotion regulation strategies with patients relates to doctors’ emotional exhaustion. Second, it tests two mechanisms that may explain those relationships. A survey of 345 general practitioners (GPs) working in a large urban community in Spain was conducted for the study. Based on Côté's (2005) social interaction model, GP satisfaction with the responses of their patients was tested as a potential interpersonal mediator between their use of automatic, surface, and deep emotion regulation strategies and their emotional exhaustion. Psychological effort was tested as a potential intrapersonal mediator in the same pathway. Regression analysis indicated that emotion regulation was associated with GP emotional exhaustion when it was performed automatically, but that it had a positive and a neutral association when it was performed using surface and deep acting respectively. The mediating role of interpersonal and intrapersonal factors helped explain the differential associations between the GPs’ emotion regulation strategies and their emotional exhaustion.