Ordinal Measures of Association

Kruskal, William

doi:10.1080/01621459.1958.10501481

Cited by 442 publications

(123 citation statements)

References 37 publications

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“…The difference in effect of methylphenidate between the two tasks within individuals was assessed using a onesample t test on the size of the difference in the Z-score of the drug effect between the tasks. Associations between drug-induced changes in cognitive performance measures, BP change values from each of the five ROIs, and trait impulsivity (BIS-11) were calculated using Kendall's tau-b coefficients, to minimize the influence of outliers on the small sample sizes (Kruskal, 1958).…”

Section: Methodsmentioning

confidence: 99%

Dopamine Release in Dissociable Striatal Subregions Predicts the Different Effects of Oral Methylphenidate on Reversal Learning and Spatial Working Memory

Clatworthy¹,

Lewis²,

Brichard³

et al. 2009

J. Neurosci.

216

178

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Previous data suggest that methylphenidate can have variable effects on different cognitive tasks both within and between individuals. This is thought to be underpinned by inverted U-shaped relationships between cognitive performance and dopaminergic activity in relatively separate fronto-striatal circuits and reflected by individual differences in trait impulsivity. Direct evidence for this is currently lacking. In this study, we demonstrate for the first time that therapeutic doses of oral methylphenidate administered to young healthy subjects result in different sized changes in D 2 /D 3 receptor availability in different regions of the human striatum and that the change in receptor availability within an individual subregion predicts cognitive performance on a particular task. Methylphenidate produced significantly different effects on reversal learning and spatial working memory tasks within individuals. Performance on the reversal learning task was predicted by the drug-induced change in D 2 /D 3 receptor availability in postcommissural caudate, measured using [ 11 C]-raclopride radioligand PET imaging, whereas performance on the spatial working memory task was predicted by changes in receptor availability in the ventral striatum. Reversal learning performance was also predicted by subjects' trait impulsivity, such that the most impulsive individuals benefited more from methylphenidate, consistent with this drug's beneficial effects on cognition in attention deficit hyperactivity disorder.

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Section: Methodsmentioning

confidence: 99%

Dopamine Release in Dissociable Striatal Subregions Predicts the Different Effects of Oral Methylphenidate on Reversal Learning and Spatial Working Memory

Clatworthy¹,

Lewis²,

Brichard³

et al. 2009

J. Neurosci.

216

178

View full text Add to dashboard Cite

show abstract

“…In Kendall-tau tests, coefficient values range from -1 to +1, where -1 means complete negative association and +1 means complete positive association (Kruskal, 1958).…”

Section: Kendall-tau Coefficientsmentioning

confidence: 99%

Corruption and Internal Fraud in the Turkish Construction Industry

Gunduz

Önder²

2012

Sci Eng Ethics

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“…For more details about Kendall's tau and Spearman's rho and their estimators, we refer to (Kendall & Stuart. 1979), (Kruskal 1958), (Lehmann 1975) and (Caperaa & Genest. 1993).…”

Section: Dependence Structurementioning

confidence: 99%

Multidimensional risk assessment for vehicle trajectories by using copulas

Koita¹,

Daucher²,

Fogli³

2014

Safety, Reliability, Risk and Life-Cycle Performance of Structures and Infrastructures

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Fight against road unsafety is a French government priority. The policy conducted since 2002 allowed to obtain undeniable success. Despite this improvement, road accidents have very serious consequences on human level for road users. The proposed methods to reduce these accidents involve independence between criteria of accident risk. The objective of this study is to estimate the multidimensional risk of failure trajectory. It consists to investigate a new method of risk assessment in order to better characterize the dependence structure between the vehicle criteria for safety acceptance. This requires the use of simulation techniques such as copulas methods. This function connects the joint probability distribution to the marginal distribution. Thus, it contains all information on the dependence structure of models. However, the difficulty of multidimensional risk is to choose the copula which capture the better dependence between criteria. To select an adequate copula must be based on a statistical test. The χ 2 test used in the framework of the adjustment of a parametric distribution to an empirical distribution is in this regard an interesting tool for the choice of copula. The experiments have shown the relevance and effectiveness of this method. The results will help to better assess the risk of failure trajectory for vehicles.

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Ordinal Measures of Association

Cited by 442 publications

References 37 publications

Dopamine Release in Dissociable Striatal Subregions Predicts the Different Effects of Oral Methylphenidate on Reversal Learning and Spatial Working Memory

Dopamine Release in Dissociable Striatal Subregions Predicts the Different Effects of Oral Methylphenidate on Reversal Learning and Spatial Working Memory

Corruption and Internal Fraud in the Turkish Construction Industry

Multidimensional risk assessment for vehicle trajectories by using copulas

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