996 resultados para Optimal tests


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There are at least two reasons for a symmetric, unimodal, diffuse tailed hyperbolic secant distribution to be interesting in real-life applications. It displays one of the common types of non normality in natural data and is closely related to the logistic and Cauchy distributions that often arise in practice. To test the difference in location between two hyperbolic secant distributions, we develop a simple linear rank test with trigonometric scores. We investigate the small-sample and asymptotic properties of the test statistic and provide tables of the exact null distribution for small sample sizes. We compare the test to the Wilcoxon two-sample test and show that, although the asymptotic powers of the tests are comparable, the present test has certain practical advantages over the Wilcoxon test.

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This study examines the relationship between morningness-eveningness orientation and time-of day on attitude change, and tests the hypothesis that people will be more persuaded when tested at their optimal time-of-day (i.e., morning for M-types and evening for E-types) than non-optimal time-of-day (i.e., evening for M-Types and morning for E-types). Two hundred and twenty participants read a message that contained either strong vs. weak quality counter-attitudinal arguments (anti-voluntary euthanasia) in the morning (9.00. a.m.) or in the evening (7.00. p.m.). When tested at their respective optimal time-of-day (for both M- and E-types) there was a reliable difference in attitude change between the strong vs. weak messages (indicating message processing had occurred) while there was no difference between strong vs. weak messages when tested at their non-optimal time-of-day. In addition, the amount of message-congruent thinking mediated the attitude change. The results show that M- and E-types pay greater attention to and elaborate on a persuasive message at their optimal time-of-day, and this leads to increased attitude change, compared to those tested at their non-optimal time-of-day. © 2012.

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The purpose of discussed optimal valid partitioning (OVP) methods is uncovering of ordinal or continuous explanatory variables effect on outcome variables of different types. The OVP approach is based on searching partitions of explanatory variables space that in the best way separate observations with different levels of outcomes. Partitions of single variables ranges or two-dimensional admissible areas for pairs of variables are searched inside corresponding families. Statistical validity associated with revealed regularities is estimated with the help of permutation test repeating search of optimal partition for each permuted dataset. Method for output regularities selection is discussed that is based on validity evaluating with the help of two types of permutation tests.

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Oomycete diseases cause significant losses across a broad range of crop and aquaculture commodities worldwide. These losses can be greatly reduced by disease management practices steered by accurate and early diagnoses of pathogen presence. Determinations of disease potential can help guide optimal crop rotation regimes, varietal selections, targeted control measures, harvest timings and crop post-harvest handling. Pathogen detection prior to infection can also reduce the incidence of disease epidemics. Classical methods for the isolation of oomycete pathogens are normally deployed only after disease symptom appearance. These processes are often-time consuming, relying on culturing the putative pathogen(s) and the availability of expert taxonomic skills for accurate identification; a situation that frequently results in either delayed application, or routine ‘blanket’ over-application of control measures. Increasing concerns about pesticides in the environment and the food chain, removal or restriction of their usage combined with rising costs have focussed interest in the development and improvement of disease management systems. To be effective, these require timely, accurate and preferably quantitatve diagnoses. A wide range of rapid diagnostic tools, from point of care immunodiagnostic kits to next generation nucleotide sequencing have potential application in oomycete disease management. Here we review currently-available as well as promising new technologies in the context of commercial agricultural production systems, considering the impacts of specific biotic and abiotic and other important factors such as speed and ease of access to information and cost effectiveness

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PURPOSE To identify the factors responsible for the poor validity of the most common aniseikonia tests, which involve size comparisons of red-green stimuli presented haploscopically. METHODS Aniseikonia was induced by afocal size lenses placed before one eye. Observers compared the sizes of semicircles presented haploscopically via color filters. The main factor under study was viewing mode (free viewing versus short presentations under central fixation). To eliminate response bias, a three-response format allowed observers to respond if the left, the right, or neither semicircle appeared larger than the other. To control decisional (criterion) bias, measurements were taken with the lens-magnified stimulus placed on the left and on the right. To control for size-color illusions, measurements were made with color filters in both arrangements before the eyes and under binocular vision (without color filters). RESULTS Free viewing resulted in a systematic underestimation of lens-induced aniseikonia that was absent with short presentations. Significant size-color illusions and decisional biases were found that would be mistaken for aniseikonia unless appropriate action is taken. CONCLUSIONS To improve their validity, aniseikonia tests should use short presentations and include control conditions to prevent contamination from decisional/response biases. If anaglyphs are used, presence of size-color illusions must be checked for. TRANSLATIONAL RELEVANCE We identified optimal conditions for administration of aniseikonia tests and appropriate action for differential diagnosis of aniseikonia in the presence of response biases or size-color illusions. Our study has clinical implications for aniseikonia management.

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Children fromdevelopedanddevelopingcountriesdifferintheirbodysizeandshapedueto markeddifferencesacrosstheirlifehistorycausedbysocial,economicandculturaldifferenceswhicharealsolinkedtotheirmotorperformance(MP).Weusedallometricmodelsto identifysize/shapecharacteristicsassociatedwithMPtestsbetweenBrazilianandPeruvianschoolchildren.Atotalof4,560subjects,2,385girlsand2,175boysaged9–15years werestudied.Heightandweightweremeasured;biological maturation wasestimated with thematurityoffsettechnique;MPmeasuresincludedthe12minuterun(12MR),handgrip strength(HG),standinglongjump(SLJ)andtheshuttlerunspeed(SR)tests;physicalactivity(PA)wasassessedusingtheBaeckequestionnaire.Amultiplicativeallometricmodel wasadoptedtoadjustforbodysizedifferencesacrosscountries.Reciprocalponderalindex (RPI)wasfoundtobethemostsuitablebodyshapeindicatorassociatedwiththe12MR, SLJ,HGandSRperformance.Apositivematurationoffset parameterwasalsoassociated withabetterperformanceinSLJ,HGandSRtests.Sexdifferenceswerefoundinallmotor tests.BrazilianyouthshowedbetterscoresinMPthantheirPeruvianpeers,evenwhen controlling fortheirbodysizedifferencesThecurrentstudyidentifiedthekeybodysize associatedwithfourbodymass-dependentMPtests.Biological maturationandPAwere associatedwithstrengthandmotorperformance.Sexdifferenceswerefoundinallmotor tests,aswellasacrosscountriesfavoringBrazilianchildrenevenwhenaccountingfortheir bodysize/shapedifferences.

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Children fromdevelopedanddevelopingcountriesdifferintheirbodysizeandshapedueto markeddifferencesacrosstheirlifehistorycausedbysocial,economicandculturaldifferenceswhicharealsolinkedtotheirmotorperformance(MP).Weusedallometricmodelsto identifysize/shapecharacteristicsassociatedwithMPtestsbetweenBrazilianandPeruvianschoolchildren.Atotalof4,560subjects,2,385girlsand2,175boysaged9–15years werestudied.Heightandweightweremeasured;biological maturation wasestimated with thematurityoffsettechnique;MPmeasuresincludedthe12minuterun(12MR),handgrip strength(HG),standinglongjump(SLJ)andtheshuttlerunspeed(SR)tests;physicalactivity(PA)wasassessedusingtheBaeckequestionnaire.Amultiplicativeallometricmodel wasadoptedtoadjustforbodysizedifferencesacrosscountries.Reciprocalponderalindex (RPI)wasfoundtobethemostsuitablebodyshapeindicatorassociatedwiththe12MR, SLJ,HGandSRperformance.Apositivematurationoffset parameterwasalsoassociated withabetterperformanceinSLJ,HGandSRtests.Sexdifferenceswerefoundinallmotor tests.BrazilianyouthshowedbetterscoresinMPthantheirPeruvianpeers,evenwhen controlling fortheirbodysizedifferencesThecurrentstudyidentifiedthekeybodysize associatedwithfourbodymass-dependentMPtests.Biological maturationandPAwere associatedwithstrengthandmotorperformance.Sexdifferenceswerefoundinallmotor tests,aswellasacrosscountriesfavoringBrazilianchildrenevenwhenaccountingfortheir bodysize/shapedifferences.