scholarly journals Nonparametric Combination (NPC): A Framework for Testing Elaborate Theories

2017 ◽  
Vol 79 (2) ◽  
pp. 688-701 ◽  
Author(s):  
Devin Caughey ◽  
Allan Dafoe ◽  
Jason Seawright



2015 ◽  
Vol 117 (1) ◽  
pp. 117-138 ◽  
Author(s):  
Luigino Barisan ◽  
Vasco Boatto ◽  
Luca Rossetto ◽  
Luigi Salmaso

Purpose – The European Union (EU) has strongly rearranged the management of EU wine policy by introducing actions for promoting wine in third countries. The purpose of this paper is to evaluate factors affecting the knowledge of Italian wines in foreign consumers, i.e., to what extend wine promotion actions can improve the consumer’s awareness or the reputation of Italian wines. As a consequence, these activities may increase the wine consumption as well as wine exports in emerging markets. Design/methodology/approach – Data have been collected through survey questionnaires where information about wine tasting, sensory satisfaction and preferences about Italian wines have been collected. The sample survey collects preferences of wine market operators in both EU and third countries. The survey, carried out from 2009 to 2011, includes 3,579 interviews classified according to four promotion actions: press conference, wine tasting, tasting course, knowledge of Italian wines. Data have been analyzed through a nonparametric combination (NPC) of dependent permutation tests to evaluate differences between and within country groups and to assess the consumer perception about Italian wines through the Keller’s model. Findings – So far, Italian wine promotion activities, supported by EU wine policy, are fragmented among in many small and sometimes low effective actions. Research results may be helpful in designing more effective promotional strategies on third countries. In particular, promotional activities which should be focussed on consumer’s appreciation of Italian wines as a brand instead of promoting specific wines or wineries. Research limitations/implications – The NPC method is a nonparametric tool which does not measure the structure of consumer’s preferences, i.e, it does give any measure of relationships among consumer’s utility and factors affecting it as it happens when a modeling approach is applied. Practical implications – Targeted promotion and information actions strongly focussed internal and external wine attributes can increase the level of knowledge in foreign consumers. It can make more efficient the marketing activity oriented to the export market. Originality/value – The NPC method offers an innovative, flexible and well-tested approach for the analysis of multivariate hypothesis when we are dealing with complex problems in wine market.







2016 ◽  
Vol 36 (2) ◽  
pp. 867-878
Author(s):  
Wang Jun ◽  
Huang Jiwei ◽  
Chen Riqing ◽  
Lin Ruiquan


2011 ◽  
Vol 77 (14) ◽  
pp. 4986-5000 ◽  
Author(s):  
Maria Elena Martino ◽  
Luca Fasolato ◽  
Filomena Montemurro ◽  
Marina Rosteghin ◽  
Amedeo Manfrin ◽  
...  

ABSTRACTThe genusAeromonashas been described as comprising several species associated with the aquatic environment, which represents their principal reservoir.Aeromonasspp. are commonly isolated from diseased and healthy fish, but the involvement of such bacteria in human infection and gastroenteritis has frequently been reported. The primary challenge in establishing an unequivocal link between theAeromonasgenus and pathogenesis in humans is the extremely complicated taxonomy. With the aim of clarifying taxonomic relationships among the strains and phenotypes, a multilocus sequencing approach was developed and applied to characterize 23 type and reference strains ofAeromonasspp. and a collection of 77 field strains isolated from fish, crustaceans, and mollusks. All strains were also screened for putative determinants of virulence by PCR (ast,ahh1,act,asa1,eno,ascV, andaexT) and the production of acylated homoserine lactones (AHLs). In addition, the phenotypic fingerprinting obtained from 29 biochemical tests was submitted to the nonparametric combination (NPC) test methodology to define the statistical differences among the identified genetic clusters. Multilocus sequence typing (MLST) achieved precise strain genotyping, and the phylogenetic analysis of concatenated sequences delineated the relationship among the taxa belonging to the genusAeromonas, providing a powerful tool for outbreak traceability, host range diffusion, and ecological studies. The NPC test showed the feasibility of phenotypic differentiation among the majority of the MLST clusters by using a selection of tests or the entire biochemical fingerprinting. A Web-based MLST sequence database (http://pubmlst.org/aeromonas) specific for theAeromonasgenus was developed and implemented with all the results.



2019 ◽  
Vol 42 (2) ◽  
pp. 185-208
Author(s):  
Atul Rajaram Chavan ◽  
Digambar Tukaram Shirke

In this article, we propose nonparametric tests for simultaneously testing equality of location and scale parameters of two multivariate distributions by using nonparametric combination theory. Our approach is to combine the data depth based location and scale tests using combining function to construct a new data depth based test for testing both location and scale parameters. Based on this approach, we have proposed several tests. Fisher's permutation principle is used to obtain p-values of the proposed tests. Performance of proposed tests has been evaluated in terms of empirical power for symmetric and skewed multivariate distributions and compared to the existing test based on data depth. The proposed tests are also applied to a real-life data set for illustrative purpose.



2017 ◽  
Vol 27 (12) ◽  
pp. 3739-3769 ◽  
Author(s):  
Rosa Arboretti ◽  
Roberto Fontana ◽  
Fortunato Pesarin ◽  
Luigi Salmaso

This paper looks at permutation methods used to deal with hypothesis testing within the survival analysis framework. In the literature, several attempts have been made to deal with the comparison of survival curves and, depending on the survival and hazard functions of two groups, they can be more or less efficient in detecting differences. Furthermore, in some situations, censoring can be informative in that it depends on treatment effect. Our proposal is based on the nonparametric combination approach and has proven to be very effective under different configurations of survival and hazard functions. It allows the practitioner to test jointly on primary and censoring events and, by using multiple testing methods, to assess the significance of the treatment effect separately on the survival and the censoring process.



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