An update on ‘a comparative study of tests for homogeneity of variance’

Tests for equality of variances using independent samples are widely used in data analysis. Conover et al. [A comparative study of tests for homogeneity of variance, with applications to the outer continental shelf bidding data. Technometrics. 1981;23:351–361], won the Youden Prize by comparing 56 variations of popular tests for variance on the basis of robustness and power in 60 different scenarios. None of the tests they compared were robust and powerful for the skewed distributions they considered. This study looks at 12 variations they did not consider, and shows that 10 are robust for the skewed distributions they considered plus the lognormal distribution, which they did not study. Three of these 12 have clearly superior power for skewed distributions, and are competitive in terms of robustness and power for all of the distributions considered. They are recommended for general use based on robustness, power, and ease of application.     

Models of the Joint Structure of Domain-Related and Global Distress: Implications for the Reconciliation of Quality of Life and Mental Health Perspectives

Research on subjective wellbeing includes studies of both domain-related and global distress. The mental health literature, though, focuses almost exclusively on global distress. This seems to be partly due to a common belief that psychological distress, and the moods that comprise distress, necessarily lack referential content. However, if that were the case it would make little sense for any study to ever focus on domain-related distress. The research presented in this report clarifies the relation between global and domain-related distress. We compare confirmatory factor analytic models of the joint relationship among symptoms of global distress with affective symptoms of distress about work, home, and physical appearance. Data are from a general population telephone survey. In the best-fitting models domain-related distress and global psychological distress are related but distinct latent variables. We discuss the theoretical and methodological implications of the models, and model choice.     

Child learning and family mealtime environment,parenting style and family functioning among preschoolers in Hong Kong

A two-wave longitudinal study on 470 parent–child dyads examined the impact of family mealtime environment, parenting style and family functioning on preschoolers’ (three to six years old) learning. Measures included parent report on parenting style, family functioning, family meal frequency, mealtime television, feeding practice, teacher/parent report of academic competence and individual assessment of preschoolers’ preschool concepts. Family mealtime environment variables were associated with pre-schoolers’ learning, in addition to parenting style and family functioning, after controlling for family income and wave 1 preschoolers’ learning. The results highlighted the importance of family mealtime environment on preschoolers’ learning.     

Changes in the gender structure: Inequality at the individual,interactional, and macro dimensions

As a society, we've made tremendous progress toward gender equality over the past several decades. Yet there remains significant inequality between women and men. Furthermore, when we look closely at some of the progress made toward gender equality, we find it considerably less impressive than surface appearances. In this article, we review the updated framework of Risman's (2017) gender structure theory and argue that it can help us make sense of the progress we've made as well as analyzing inequality as it persists between women and men. Using gender structure theory, we then show how gender is simultaneously reproduced and contested across the individual, interactional, and macro levels of society within 3 major social domains: work, family, and gender identity.     

Education,Skills, and Wage Gaps in Canada and the United States

We analyse data from the Programme for the International Assessment of Adult Competencies to reveal that immigrants in Canada and the United States make over $200 less per month than native‐born workers. In the United States, immigrants disproportionately work in low‐wage occupations, leading to large mean national differences between immigrants and native workers. The wage differential disappears after accounting for education and cognitive skills, indicating policies must focus on reducing education and skill gaps in the United States. In Canada, an immigrant wage gap persists in nearly all occupational fields, suggesting that the better skilled and educated immigrants in Canada are not receiving the same wage premium as native workers. We close with implications for policy and future research.     

A general class of test statistics for Van Valen's Red Queen hypothesis

Van Valen's Red Queen hypothesis states that within a homogeneous taxonomic group the age is statistically independent of the rate of extinction. The case of the Red Queen hypothesis being addressed here is when the homogeneous taxonomic group is a group of similar species. Since Van Valen's work, various statistical approaches have been used to address the relationship between taxon age and the rate of extinction. We propose a general class of test statistics that can be used to test for the effect of age on the rate of extinction. These test statistics allow for a varying background rate of extinction and attempt to remove the effects of other covariates when assessing the effect of age on extinction. No model is assumed for the covariate effects. Instead we control for covariate effects by pairing or grouping together similar species. Simulations are used to compare the power of the statistics. We apply the test statistics to data on Foram extinctions and find that age has a positive effect on the rate of extinction. A derivation of the null distribution of one of the test statistics is provided in the supplementary material.     

Estimation and Inference Procedures for Semiparametric Distribution Models with Varying Linear‐Index

More flexible semiparametric linear‐index regression models are proposed to describe the conditional distribution. Such a model formulation captures varying effects of covariates over the support of a response variable in distribution, offers an alternative perspective on dimension reduction and covers a lot of widely used parametric and semiparameteric regression models. A feasible pseudo likelihood approach, accompanied with a simple and easily implemented algorithm, is further developed for the mixed case with both varying and invariant coefficients. By justifying some theoretical properties on Banach spaces, the uniform consistency and asymptotic Gaussian process of the proposed estimator are also established in this article. In addition, under the monotonicity of distribution in linear‐index, we develop an alternative approach based on maximizing a varying accuracy measure. By virtue of the asymptotic recursion relation for the estimators, some of the achievements in this direction include showing the convergence of the iterative computation procedure and establishing the large sample properties of the resulting estimator. It is noticeable that our theoretical framework is very helpful in constructing confidence bands for the parameters of interest and tests for the hypotheses of various qualitative structures in distribution. Generally, the developed estimation and inference procedures perform quite satisfactorily in the conducted simulations and are demonstrated to be useful in reanalysing data from the Boston house price study and the World Values Survey.     

Do Associations Between Pleasure Ratings and Condom Use During Penile–Vaginal Intercourse Vary by Relationship Type?: A Study of Canadian University Students

Research suggests the relationship between pleasure and condom use during penile–vaginal intercourse (PVI) is associated with relationship status. This online study examined pleasure ratings and condom use at last PVI, stratifying by partner type, among a national sample of Canadian university students. Participants were 715 undergraduates (60.7% women, 39.3% men) who reported on their most recent sexual experience. Condom use decreased with level of relationship commitment, whereas ratings of pleasure increased. Overall, participants were more likely to rate their most recent PVI as Very pleasurable when condoms were not used compared to when condoms were used. However, when stratified by partner type, these differences largely disappeared. For women, with one exception, there were no differences in pleasure between PVI with and without condoms across most partner-type categories. Women in committed dating relationships were more likely to report their last PVI as very pleasurable if condoms were not used than women in these same relationships who had used condoms. Across relationship categories, men who did and did not use condoms did not differ in terms of their pleasure ratings. The results of this study suggest relationship context should be taken into account when assessing condom use experiences.