Search results for "Rank correlation"
showing 10 items of 53 documents
Multivariate nonparametric tests of independence
2005
New test statistics are proposed for testing whether two random vectors are independent. Gieser and Randles, as well as Taskinen, Kankainen, and Oja have introduced and discussed multivariate extensions of the quadrant test of Blomqvist. This article serves as a sequel to this work and presents new multivariate extensions of Kendall's tau and Spearman's rho statistics. Two different approaches are discussed. First, interdirection proportions are used to estimate the cosines of angles between centered observation vectors and between differences of observation vectors. Second, covariances between affine-equivariant multivariate signs and ranks are used. The test statistics arising from these …
Multivariate Nonparametric Tests
2004
Multivariate nonparametric statistical tests of hypotheses are described for the one-sample location problem, the several-sample location problem and the problem of testing independence between pairs of vectors. These methods are based on affine-invariant spatial sign and spatial rank vectors. They provide affine-invariant multivariate generalizations of the univariate sign test, signed-rank test, Wilcoxon rank sum test, Kruskal–Wallis test, and the Kendall and Spearman correlation tests. While the emphasis is on tests of hypotheses, certain references to associated affine-equivariant estimators are included. Pitman asymptotic efficiencies demonstrate the excellent performance of these meth…
Factors Differentiating Rural and Urban Population in Determining Anxiety and Depression in Patients with Chronic Cardiovascular Disease: A Pilot Stu…
2021
The aim of this cross-sectional study was to analyze selected variables differentiating rural from urban populations, as well as identify potentially increased levels of depression and anxiety in patients with chronic cardiovascular disease. The study was carried out in 193 patients. The study used the Camberwell Assessment of Need Short Appraisal Schedule (CANSAS), the Health Behavior Inventory Questionnaire (HBI), the WHOQOL-BREF Quality of Life Questionnaire, and the Hospital Anxiety and Depression Scale–Modified Version (HADS-M). Spearman’s rank correlation coefficient test and logistic regression were used for analyses. In rural patients, we observed a relationship between anxiety and …
Influence of nerve of origin and tumor size of vestibular schwannoma on dynamic posturography findings.
2006
Condition 5-score (C5S) and vestibular ratio (VER) correlate, but condition-6-score (C6S) and mean overall balance score (MOBS) do not, with the size of an inferior vestibular nerve (IVN) vestibular schwannoma (VS). In IVN VS patients the visual system plays a major role in the maintenance of postural stability.To test whether the size of a superior vestibular nerve (SVN) or IVN VS, as measured on MRI scans, correlates with computerized dynamic platform posturography (CDPP) findings and whether CDPP findings could preoperatively predict the nerve of origin of the VS.This was a retrospective study. Seventy-five consecutive VS patients were evaluated. C5S, C6S, VER, and MOBS were evaluated. S…
Element weighted Kemeny distance for ranking data
2021
Preference data are a particular type of ranking data that arise when several individuals express their preferences over a finite set of items. Within this framework, the main issue concerns the aggregation of the preferences to identify a compromise or a “consensus”, defined as the closest ranking (i.e. with the minimum distance or maximum correlation) to the whole set of preferences. Many approaches have been proposed, but they are not sensitive to the importance of items: i.e. changing the rank of a highly-relevant element should result in a higher penalty than changing the rank of a negligible one. The goal of this paper is to investigate the consensus between rankings taking into accou…
Consensus measures for preference rankings with ties: an approach based on position weighted Kemeny distance
2018
Preference data are a particular type of ranking data where some subjects (voters, judges, ...) give their preferences over a set of alternatives (items). It happens, in most of the real cases, that some items receive the same preference by a judge, giving raise to a ranking with ties. The purpose of our paper is to investigate on the consensus between rankings with ties taking into account the importance of swapping elements belonging to the top (or to the bottom) of the ordering (position weights). Combining the structure of the Taux proposed by Emond and Mason and the class of weighted Kemeny-Snell distances, we propose a position weighted rank correlation coefficient to compare rankings…
Stress Assessment of Vestibular Endurance Training for Civil Aviation Flight Students Based on EEG
2021
AbstractObjectiveThe main goal of our study is to clarify the EEG characteristics of the stress response caused by vestibular endurance training under the real conditions.MethodsTen pilot trainees received a series of acute anti-vertigo training stimulations on the rotary ladder while recording electroencephalographic data (64 electrodes). Afterwards, the subject’s anti-vertigo ability was tested for the best performance after 1 month of training, and verifying whether it is relating to the EEG signals we collected before.Results(1) The absolute power ofαwaves in the C3 and C4 regions is same as the difference between 1 min before and 2 min after stimulation, and their activity is enhanced …
Sulfites and the Wine Metabolome
2017
International audience; In a context of societal concern about food preservation, the reduction of sulfite input plays a major role in the wine industry. To improve the understanding of the chemistry involved in the SO2 protection, a series of bottle aged Chardonnay wines made from the same must, but with different concentrations of SO2 added at pressing were analyzed by ultrahigh resolution mass spectrometry (FT-ICR-MS) and excitation emission matrix fluorescence (EEMF).Metabolic fingerprints from FT-ICR-MS data could discriminate wines according to the added concentration to the must but they also revealed chemistry-related differences according to the type of stopper, providing a wine me…
Head-to-head comparison of contemporary heart failure risk scores.
2021
Altres ajuts: acords transformatius de la UAB Aims: Several heart failure (HF) web-based risk scores are currently used in clinical practice. Currently, we lack head-to-head comparison of the accuracy of risk scores. This study aimed to assess correlation and mortality prediction performance of Meta-Analysis Global Group in Chronic Heart Failure (MAGGIC-HF) risk score, which includes clinical variables + medications; Seattle Heart Failure Model (SHFM), which includes clinical variables + treatments + analytes; PARADIGM Risk of Events and Death in the Contemporary Treatment of Heart Failure (PREDICT-HF) and Barcelona Bio-Heart Failure (BCN-Bio-HF) risk calculator, which also include biomarke…
LI-RADS ancillary features favoring benignity: is there a role in LR-5 observations?
2021
The Liver Imaging Reporting and Data System algorithm allows category downgrade in the presence of ancillary features (AFs) favoring benignity, even in observations categorized as LR-5. This study aims to assess the role of AFs favoring benignity in LR-5 observations and their impact on category downgrade. This study included high-risk patients with at least one LR-5 observation imaged with gadoxetate disodium MRI. Three readers with different experience levels independently evaluated the presence of AFs favoring malignancy (not hepatocellular carcinoma (HCC) in particular and HCC in particular) and AFs favoring benignity. Category downgrade was considered possible in the presence of ≥ 1 AF…