The use of repeated measures, where the same subjects are tested under a number of conditions, has numerous practical and statistical benefits. For one thing it reduces the error variance caused by between-group individual differences, however, this reduction of error comes at a price because repeated measures designs potentially introduce covariation between experimental conditions (this is be...

A case is made for the use of hierarchical models in the analysis of generalization gradients. Hierarchical models overcome several restrictions that are imposed by repeated measures analysis-of-variance (rANOVA), the default statistical method in current generalization research. More specifically, hierarchical models allow to include continuous independent variables and overcomes problematic a...

In this contribution we generalize the test of sphericity as a test of stationarity for time-series. The sphericity statistics is in our case a measure of distance between the empirical correlations calculated on two contiguous segments of the same process. We prove that under the hypothesis of stationarity the logarithm of the sphericity converges in distribution to a quadratic form in a multi...

Posterior glenohumeral joint dislocation is an uncommon injury and is associated with bony and ligamentous disruption. It requires prompt diagnosis and early treatment to prevent acute or recurrent instability and subsequent dysfunction. Reverse Hill-Sachs lesions associated with this injury are challenging to treat, and optimal treatment is controversial. Treatment methods can be divided into ...

BACKGROUND Most patients with implantable cardioverter-defibrillator (ICD) implantation fail to utilize the device resulting in increasing societal costs and patient exposure to device morbidity. We sought to determine whether volumetric cardiovascular magnetic resonance (CMR) left ventricular (LV) spherical remodeling predicts future ventricular arrhythmias in primary ICD patients with reduced...

This paper proposes a test for the null of sphericity in a …xed e¤ects panel data model. It uses the Random Matrix Theory based approach of Ledoit and Wolf (2002) to test for the null of sphericity of the error terms in a …xed e¤ects panel model with a large number of cross-sectional units and time series observations. Since the errors are unobservable, the residuals from the …xed e¤ects regres...

Reduction of pH over the range 6.0-4.5 rereduced elasticity occurred at calculated suits in a decrease of erythrocyte deformaintracellular pH values at which solubility bility in parallel with the induced progresin vitro of extracted erythrocyte spectrin is sive sphericity of cells. At low deformation also markedly reduced. The parallel derates employed, increase of hemoglobin crease of deforma...

This study aims to investigate the effects of violations of the sphericity assumption on Type I error rates for different methodical approaches of repeated measures analysis using a simulation approach. In contrast to previous simulation studies on this topic, up to nine measurement occasions were considered. Therefore, two populations representing the conditions of a violation vs. a non-violat...

Abstract This manuscript considers locally best invariant tests for sphericity in heterogeneous panel models, which are given as weighted sums of individual tests. An exact integral expression and a saddlepoint approximation for their null distributions are provided. The saddlepoint approximation generalizes the earlier result of Broda, Paolella, and Tchopourian (2006). Despite having been deri...

Since rocks are aggregates of mineral particles, the effect of mineral microstructure on macroscopic mechanical behaviors of rocks is inneglectable. Rock samples of four different particle shapes are established in this study based on clumped particle model, and a sphericity index is used to quantify particle shape. Model parameters for simulation in PFC are obtained by triaxial compression tes...