Hypothesis test for paired samples in the presence of missing data

Missing data are present in almost all statistical analysis. In simple paired design tests, when some subject has one of the involved variables missing in the so-called partially overlapping samples scheme, it is usually discarded for the analysis. The lack of consistency between the information reported in the univariate and multivariate analysis is, perhaps, the main consequence. Although the randomness on the missing mechanism (missingness completely at random) is an usual and needed assumption for this particular situation, missing data presence could lead to serious inconsistencies on the reported conclusions. In this paper, the authors develop a simple and direct procedure which allows using the whole available information in order to perform paired tests. In particular, the proposed methodology is applied to check the equality among the means from two paired samples. In addition, the use of two different resampling techniques is also explored. Finally, real-world data are analysed.     

Evaluation of Multicriteria Decision Analysis Algorithms in Food Safety: A Case Study on Emerging Zoonoses Prioritization

Decision making in food safety is a complex process that involves several criteria of different nature like the expected reduction in the number of illnesses, the potential economic or health-related cost, or even the environmental impact of a given policy or intervention. Several multicriteria decision analysis (MCDA) algorithms are currently used, mostly individually, in food safety to rank different options in a multifactorial environment. However, the selection of the MCDA algorithm is a decision problem on its own because different methods calculate different rankings. The aim of this study was to compare the impact of different uncertainty sources on the rankings of MCDA problems in the context of food safety. For that purpose, a previously published data set on emerging zoonoses in the Netherlands was used to compare different MCDA algorithms: MMOORA, TOPSIS, VIKOR, WASPAS, and ELECTRE III. The rankings were calculated with and without considering uncertainty (using fuzzy sets), to assess the importance of this factor. The rankings obtained differed between algorithms, emphasizing that the selection of the MCDA method had a relevant impact in the rankings. Furthermore, considering uncertainty in the ranking had a high influence on the results. Both factors were more relevant than the weights associated with each criterion in this case study. A hierarchical clustering method was suggested to aggregate results obtained by the different algorithms. This complementary step seems to be a promising way to decrease extreme difference among algorithms and could provide a strong added value in the decision-making process.     

Corporate social responsibility,financial performance and risk in times of economic instability

Journal of Management and Governance - This article examines the relationship between the social performance of companies and their financial performance, analyzed from the systematic risk...     

Optimal classification scores based on multivariate marker transformations

AStA Advances in Statistical Analysis - Modern science frequently involves the study of complex relationships among effects and factors. Flexible statistical tools are commonly used to visualize...     

A fast greedy sequential heuristic for the vertex colouring problem based on bitwise operations

In this paper a fast greedy sequential heuristic for the vertex colouring problem is presented. The suggested algorithm builds the same colouring of the graph as the well-known greedy sequential heuristic in which on every step the current vertex is coloured in the minimum possible colour. Our main contributions include introduction of a special matrix of forbidden colours and application of efficient bitwise operations on bit representations of the adjacency and forbidden colours matrices. Computational experiments show that in comparison with the classical greedy heuristic the average speedup of the developed approach is 2.6 times on DIMACS instances.     

Student views on campus sexual assault

Abstract

Objective: To report on college student opinions about the scope of college sexual misconduct (CSM), suggested university sanctions, and treatment of students found responsible of CSM.

Participants: In all, 23?US undergraduate students (14 females and 9 males) with a mean age of 20 years.

Methods: Students participated either in female, male, or mixed-sex focus groups that facilitated the discussion of factors related to CSM.

Results: Students provided in-depth feedback on the climate on US college campuses and factors related to CSM. They agreed upon CSM risk factors and context characteristics, but raised different male and female issues across sex groups. They further provided resolute suggestions for the solution of CSM, experienced treatment barriers, and limited victim reporting.

Conclusion: Student focus groups provide important information about the scope of CSM and offer valuable suggestions for the solution of the problem that may be crucial for the development of successful sexual assault interventions.     

Validating a primed identity leads to expectations of group-relevant outcomes / La validación de una identidad previamente primada facilita que se anticipen respuestas de discriminación

Abstract

We argue that a person’s identity can be changed by seemingly irrelevant primes to the point where one expects to be treated as a member of an activated social group. We further argue that primes should only influence the self to the extent that they are seen as valid. We experimentally manipulated conditions that foster perceptions of prime validity using a head movement induction. Previous research has linked head nodding to higher levels of confidence than head shaking. Participants primed with the African American stereotype (versus control) expected more future discrimination, but only if they were nodding their heads. Results are discussed with respect to research on priming and validation processes.     

Asymptotic properties of a human age distribution under a continuous net maternity function

A useful and intuitively appealing proposition in theoretical demography asserts that the age distribution of a closed human populationis asymptotically independent of this shapein thedistant past, and is therefore exclusively determined by the historyof fertility and mortalitythat has prevailed during a reasonably long period of time. The mathematical foundations of this ergodic principle arelaid out in this article and thedetailsof its proofareworked out afteremphasizing an intuitive understanding of the process through which an age distribution tends to "forget" its past. The tendency for an unchanging schedule of vital ratesto produce a fixed agestructure in a closed population, is presented as a corollary of the main proposition dealt with in this article.     

Posttraumatic stress disorder and occupational performance: building resilience and fostering occupational adaptation

Resilience and vulnerability refer to an individual's capacity to persevere in the face of adversity. Resiliency and vulnerability are distinctive personal characteristics influenced by environmental factors such as socio-cultural and institutional contexts. Resiliency and vulnerability are not absolute; they are psychosocial constructs of a phenomenological continuum. Hence, a resilient individual is not invincible to all life events but has the capacity to endure in most circumstances. Clients who sustain traumatic injuries or witness traumatic events have a greater vulnerability to stress disorders like posttraumatic stress disorder (PTSD). Occupational therapy practitioners should be cognizant of a client's resilient and adaptive capacities when providing services to a client who has endured a traumatic event. This paper explores resilience theory and its application to occupational therapy practice.     

TRADE PROTECTION AND THE ROLE OF CAMPAIGN CONTRIBUTIONS IN U.S. FOOD AND TOBACCO INDUSTRIES

This article examines the determinants of both trade protection and campaign contributions for a sample of U.S. food and tobacco industries. Empirical findings indicate that while market structure variables are significant, campaign contributions are the key factor in explaining the inter-industry levels of trade barriers in those industries studied. Thus, regardless of industry characteristics, campaign contributions have a strong persuasive role, rather than the facilitative role that most previous studies suggest.