Search results for "variance"
showing 10 items of 2030 documents
Changes from 1986 to 2006 in reasons for liking leisure-time physical activity among adolescents
2016
Reasons for participating in physical activity (PA) may have changed in accordance with the general modernization of society. The aim is to examine changes in self-reported reasons for liking leisure-time physical activity (LTPA) and their association with self-reported LTPA over a 20-year period. Data were collected among nationally representative samples of 13-year-olds in Finland, Norway, and Wales in 1986 and 2006 (N = 9252) as part of the WHO cross-national Health Behaviour in School-aged Children (HBSC) study. Univariate ANOVAs to establish differences according to gender, year, and country were conducted. In all countries, 13-year-olds in 2006 tended to report higher importance in te…
Cyberbullying among Adolescents: Psychometric Properties of the CYB-AGS Cyber-Aggressor Scale
2020
The present study aims to analyze the psychometric properties of the revised version of the Adolescent Cyber-Aggressor scale (CYB-AGS). This scale is composed of 18 items that measure direct and indirect cyberbullying. A cross-sectional study was conducted using two independent samples of adolescents. The first sample included 1318 adolescents (52.6% girls) from 12 to 16 years old (M = 13.89, SD = 1.32). The second sample included 1188 adolescents (48.5% boys) from 12 to 16 years old (M = 14.19, SD = 1.80). First, to study the psychometric properties of the CYB-AGS, exploratory factor analysis was performed on Sample 1. Results indicated a two-factor structure: direct cyber-aggression and i…
Construct validity of the anxiety sensitivity index-3 in clinical samples
2012
"Using two clinical samples of patients, the presented studies examined the construct validity of the recently revised Anxiety Sensitivity Index-3 (ASI-3). Confirmatory factor analyses established a clear three-factor structure that corresponds to the postulated subdivision of the construct into correlated somatic, social, and cognitive components. Participants with different primary clinical diagnoses differed from each other on the ASI-3 subscales in theoretically meaningful ways. Specifically, the ASI-3 successfully discriminated patients with anxiety disorders from patients with nonanxiety disorders. Moreover, patients with panic disorder or agoraphobia manifested more somatic concerns …
Catastrophic risks and the pricing of catastrophe equity put options
2021
In this paper, after a review of the most common financial strategies and products that insurance companies use to hedge catastrophic risks, we study an option pricing model based on processes with jumps where the catastrophic event is captured by a compound Poisson process with negative jumps. Given the importance that catastrophe equity put options (CatEPuts) have in this context, we introduce a pricing approach that provides not only a theoretical contribution whose applicability remains confined to purely numerical examples and experiments, but which can be implemented starting from real data and applied to the evaluation of real CatEPuts. We propose a calibration framework based on his…
Minimising value-at-risk in a portfolio optimisation problem using a multi-objective genetic algorithm
2011
[EN] In this paper, we develop a general framework for market risk optimisation that focuses on VaR. The reason for this choice is the complexity and problems associated with risk return optimisation (non-convex and non-differential objective function). Our purpose is to obtain VaR efficient frontiers using a multi-objective genetic algorithm (GA) and to show the potential utility of the algorithm to obtain efficient portfolios when the risk measure does not allow calculating an optimal solution. Furthermore, we measure differences between VaR efficient frontiers and variance efficient frontiers in VaR-return space and we evaluate out-sample capacity of portfolios on both bullish and bearis…
Eco depletion: The impact of hunger on prosociality by means of environmentally friendly attitudes and behavior
2021
Abstract The present research investigated the impact of hunger on prosociality in a consumer choice context by means of environmentally friendly attitudes and behavior. Two eye-tracking studies were conducted with hunger measured (Study 1) and manipulated (Study 2). The data were analyzed through bivariate correlations, Pearson's chi-square tests, and analyses of variance (ANOVAs). Our findings, based on cross-sectional and experimental evidence from field and lab settings, revealed that hungry consumers express more prosocial attitudes than their satiated counterparts in terms of general environmental concerns and importance ratings of buying eco-labeled products. However, we found no sig…
The effect of an advertisement’s colour on emotions evoked by attitude towards the ad
2007
Despite its importance surprisingly little is known about the influence of colour in advertising. This paper studies the effects of the three components of an ad’s colour (hue, saturation and lightness) on the emotions it evokes and on attitudes towards it. It is assumed that the influence of colour varies with the individual, whose optimal stimulation level (OSL) is considered a moderator variable. Analyses of covariance were conducted. The results show that OSL is a moderator variable accounting for the relations between hue and the pleasure evoked by the ad, and hue and the attitude towards the ad. Moreover, OSL proves to be a moderator for the relation between saturation and the same de…
In vitro carious lesion detection on D-, E-, and F-speed radiographic films
2004
Abstract Objectives To compare the accuracy in detection of interproximal natural carious lesions in vitro between Ultraspeed (D), Ektaspeed Plus (E), and Insight (F) radiographic films. Study design Ten observers indicated on a 5-point scale their confidence in detecting an interproximal lesion in 240 surfaces (120 extracted teeth) with noncavitated carious lesions. Truth was assessed microscopically from hemisections. The areas (Az) beneath receiver operating characteristic (ROC) curves were pairwise compared and used for a 2-way analysis of variance. Results Az values were significantly correlated with observers ( P = .002; Eta = 0.671) and film type ( P = .003; Eta = 0.412). E differe…
Effects of endodontic treatment on apparent Young’s modulus of human teeth: in vitro study using speckle interferometry
2012
The introduction of new techniques for endodontic procedures requires the analysis of the biomechanical behavior of dental structures. Digital speckle shearing pattern interferometry (DSSPI) is a nondestructive optical measuring technique that allows one to directly quantify deformations in teeth that are subjected to stress. DSSPI technique was applied to measure small deformations caused by flexion in different types of teeth. The test was carried out both before and after endodontic treatment with the ProTaper method in order to evaluate the variation of dental elasticity, taking into the account the type of tooth and the endodontic treatment. The results obtained show that dental elasti…
FSW of AA2139-T8 Butt joints for aeronautical applications
2011
The effect of process parameters on mechanical and microstructural properties of AA 2139 T8 joints produced by friction stir welding (FSW) was analysed by means of statistical tools. Three different parameters were taken into account: angular speed ( ω), welding speed ( va), and plunging depth ( p); each of them was varied on three levels. Forces and temperatures achieved during the welding were monitored and analysed for all joints. An accurate microstructural analysis was performed: the occurrence of some remarkable defects, typical of FSW, such as tunnel or lack of penetration, was related to actual process parameters adopted. The extension of each FSW characteristic zone was measured a…