Haut PDF A Mean Difference is an Effect Size

A Mean Difference is an Effect Size

A Mean Difference is an Effect Size

9 So how should we use the term? From all this, it seems clear that “effect size” can be used both in a broad sense and in a narrow sense , provided that the author is consistent and clarifies what they are talking about. In my opinion, the broad sense is more useful in general methodological discussions. The terms “unstandardized (or simple) effect size” and “standardized effect size” are widely used and perfectly capable of resolving any ambiguity. Using “effect size” in a broad sense doesn’t commit anyone to any particular statistical reporting practice. Anyone is free to point out limitations and possible dangers of reporting unstandardized effect sizes or standardized effect sizes. When the truth of a statement depends on whether it refers to standardized or unstandardized effect sizes, the term “effect size” without a qualifier should simply be avoided. Using “effect size” to mean only “standardized effect sizeis problematic because it requires finding another term for unstandardized effect sizes. I don’t recall any user of the narrow definition proposing such a term, and even if they did, a different term could give the wrong impression that unstandardized and standardized effect sizes have nothing in common. Cohen and others were clear about the analogies between the two.
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Is the fish-hook effect in hydrocyclones a real phenomenon?

Is the fish-hook effect in hydrocyclones a real phenomenon?

or not. Majumder et al. [5] have provided a mechanistic argument supporting the occurrence of fish-hook in all centrifugal separators while treating fine and ultra fine particles. The basis of their argument is that in a centrifugal force field, there is a sudden drop in relatively coarser particles settling velocities due to Reynolds number restrictions. As scientists and practitioners alike share different opinions about this phenomenon, an attempt has been made here to assess whether measurement errors could possibly be responsible, on their own ac- count, for the fish-hook effect. For the sake of clarity, it is emphasized that the fish-hook effect that is being investigated in this work is that caused by particle size only. This work is not concerned with other factors that can also affect classification, such as density variations
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The Market Size Effect in Endogenous Growth Reconsidered

The Market Size Effect in Endogenous Growth Reconsidered

The intuition regarding this result is best understood when considering a country’s total labor endowment L as the product of the size of the labor force N and an individual labor productivity parameter h: L = hN . In both our endogenous growth frameworks, the knowledge spillovers (i.e. increasing returns of the knowledge-creation function) lead to the traditional scale effect: a larger labor supply L leads to a higher growth rate. Whether this increase in L stems from an increase in h or in N however matters for the direction of the market-size effect, which operates on the demand side and stems from the use of variable elasticity preference classes. A larger population size N entails a decrease in firms’ endogenous mark-ups, which automatically leads to an more-than-proportional increase in the number of consumption good units being produced, finally ending up in a proportionally lower share of labor being devoted to R&D: the market size effect on growth is negative, dampening the positive scale effect. On the other hand, a higher level of qualification h (hence a higher income per capita) leads to higher mark-ups and a proportionally higher share of labor devoted to R&D: the market size effect on growth is positive, strenghtening the scale effect.
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Size effect regarding fatigue evaluation of asphalt mixtures

Size effect regarding fatigue evaluation of asphalt mixtures

3.2.2. Size effect on fatigue life The fatigue life of each specimen is fixed to the number of loading cycles leading to a 50% decrease of the sample stiffness. Size effects are classically explored as the variation of a resistance parameter such as material failure stress. Concerning fatigue on notched specimen, the crack propaga- tion speed is studied in terms of Paris law parameters (Carpinteri et al., 2004; Ba˘zant et al., 1991). In our case dealing with the growth of a damaged zone from a smooth surface, size effects exist but no models are available in the literature. As a first ap- proach for fatigue of asphalt mixture, we can explore the size effect on the number of cycles to failure (fatigue life) of each specimen. The fatigue life is a relevant indicator of the material resistance to fatigue but dependant on the loading level, so we will consider each loading level as an independent specimen set.
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Bias and precision of methods for estimating the difference in restricted mean survival time from an individual patient data meta-analysis

Bias and precision of methods for estimating the difference in restricted mean survival time from an individual patient data meta-analysis

In meta-analyses or in multicenter clinical trials, there is a need to take into account the trial or center effect to avoid the Simpson’s paradox that may lead to biased estimates [11–13]. Different authors have discussed the use of Cox models with either stratification or fixed effect, or random effects to account for the center effect in a multicenter clinical trial [14–16] or the trial effect in a meta-analysis [17–20] in presence of baseline haz- ard heterogeneity and/or treatment effect heterogeneity between centers or trials. Several papers have also com- pared one-stage or two-stage methods to estimate the hazard ratio in individual patient data (IPD) meta- analyses [20–22]. All these studies focused on the esti- mation of the treatment effect through the use of the hazard ratio, but so far only one has focused on the use of the rmstD t ð Þ in IPD meta-analyses [6]. In this latter  study, Wei and colleagues investigated three two-stage methods to estimate the rmstD t ð Þ from an IPD meta-  analysis: two non-parametric methods – one based on pseudo-values [23] and one based on the Kaplan-Meier estimate – and a flexible parametric survival model [24]. In their study, the rmstD t ð Þ was estimated as an aggre-  gation of the rmstD t ð Þ estimated in each trial using a  fixed effect meta-analysis model. The authors showed via simulations and two case studies that the three methods produced similar results in terms of bias and coverage probability of the confidence intervals.
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What does it mean to say that economics is performative?

What does it mean to say that economics is performative?

scrutiny on moral grounds. Millo has shown how these financial products were gradually disentangled from such moral issues and dissociated from gambling (Millo 2003). MacKenzie notes that with the Black-Scholes-Merton model this disentanglement is complete. The Black-Scholes formula defends the legitimacy of the very idea of an options market, on which rational calculations can be made. It imposes the market that it describes, by transforming options and derivatives into economic goods whose prices can be calculated objectively. The accusation of gambling and immorality automatically falls away. MacKenzie adds – and this point is strategic – that a difference is thus created: the new market is different from the preceding one. Economists do not simply legitimize, reveal or express practices and existing models: "The Black-Scholes-Merton model did more than simply express price patterns that were already there. The use of models altered price patterns […]." Of interest from the point of view of convergence, under consideration here, is the fact that a competing economics, born before and outside academia (an economics in the wild), helped to lay the ground by furthering this disentanglement. The economics in question was chartism, the history of which has been studied in detail by Preda. Apart from competition between the two forms of economics (Chartism assumes the existence of significant regularities in the forms of price variations, whereas the Black-Scholes-Merton model posits a random walk), there is profound agreement on the economic nature of options (which no longer risk being likened to gambling). This might explain why chartist practices are still being used in the field, in parallel with or as a complement to the Black-Scholes-Merton model.
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Effect of solvent on silicon nanoparticle formation and size: a mechanistic study

Effect of solvent on silicon nanoparticle formation and size: a mechanistic study

provide evidence supporting this mechanism. By simply changing the solvent from one glycol ether to another, the Si NP size distribution is significantly altered. Fig. 1 shows representative TEM images and histograms of the size distribution of Si NPs synthesized in four different glycol ethers. The results are not immediately logical, the trend in size is not linearly connected to the number of ether units, and oddly THF produces particles where its linear analogue, diethyl ether, does not. The smallest Si NPs were obtained in diglyme, having an average diameter of 6 ± 2 nm. Si NPs synthesized in THF have a size centred around 8 ± 8 nm. The synthesis in glyme offers a large range of Si NP sizes: from 5 to 60 nm; however half of the NPs have a diameter between 5 and 10 nm. In tetraglyme, a size maximum distribution occurs at 15 nm, with a substantial quantity of particles being larger than 20 nm. Perhaps the substantially larger size observed in tetraglyme is due to its viscosity, slowing NP diffusion away from the reactive surface. Pure, crystalline Si NPs are produced by this room temperature method, as confirmed with high resolution transmission electron microscopy (HRTEM) and Raman spectroscopy (Fig. 2). The Si NPs contain diffraction planes, visible using HRTEM (Fig. 2a). The d-spacing for the planes in this orientation were 0.19 nm, which correspond to the {220} hkl plane for the diamond cubic structure. The selected area electron diffraction (SAED) pattern indexes to the [-111] zone axis of cubic silicon, the expected crystallographic structure. Si nanoparticles with a chlorinated surface become charged by observation under the electron beam and thus leave the TEM grid after ~6 s of exposure time. This short window of observation did not allow us to do EDX spectra of the silicon nanoparticles. However, we performed electron diffraction on particles of all sizes and
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Effect of Prostaglandins Pge2 and Pgf Alpha 2 on the Mean Plaque Size of Bovine Herpesvirus 1

Effect of Prostaglandins Pge2 and Pgf Alpha 2 on the Mean Plaque Size of Bovine Herpesvirus 1

are associated with an increase of corticosteroid blood levels in cattle. These support the hypothesis that glucocorticoids act as inducers of reactivation of BHV-1 (Sheffy and Davies 1972, Thiry et al 1985 c, 19871. Other stimuli of reactivation, ie supe- rinfection with parainfluenza 3 (PI-3) (Mensik et al 1976) and infestation with Dictyocaulus viviparus (Msolla et al 1983, Thiry et al 1985 b), do not directly produce an increase of corticosteroid blood levels. They may represent stressful conditions for cattle, but other mechanisms may be proposed in these two cases. The possible implication of pros- taglandins in the appearance of recurrent lesions
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Intergenerational Educational Mobility : is there a religion effect in France?

Intergenerational Educational Mobility : is there a religion effect in France?

PRELIMINARY AND INCOMPLETE: PLEASE DO NOT QUOTE Abstract: This paper explores intergenerational educational mobility for three groups of individuals: Christian natives, Christian immigrants and Muslim immigrants. We develop an econometric specification for educational attainment which shows that a higher level of parent education increases differently the child education among the three groups with a special advantage for daughters. We find higher intergenerational correlation for Christian natives than for Muslims immigrants, but an intermediate level for Christian immigrants. For the three communities, we show an advantage for mother education; however this advantage differs between daughters and sons. Furthermore, we find significant effects of family variables such as birth order, family size or sibling composition which vary among the three groups. The gap between Christian and Muslim immigrants remains approximately low and a possible convergence of education levels is possible given an educational system mainly public and free.
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Is the fish-hook effect in hydrocyclones a real phenomenon?

Is the fish-hook effect in hydrocyclones a real phenomenon?

2. Accounting for particle size distribution measurement error in estimation of the partition function of the hydrocyclone 2.1. Mass balance solution with particle size distribution error Mass balancing is an important topic in extractive metallurgy. This section recaps on the set of equations that can be used to reconcile the measured particle size distributions around a hydrocyclone. The purpose is to give utter transparency to the approach that is used in this paper for propagating the experimental particle size distributions' measurement errors right through to the estimation of the error associated with the partition function of the hydrocyclone. One side value of this section is to give the practitioner a summarized account of results that can be readily used to estimate the partition function from measurements. The results that are presented hereafter are largely based on the two-product mass balancing solution published by Bazin and Hodouin [10] . Notations follow closely those of these authors also so the reader can refer back to their original work without obfuscating change in notation.
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Effect of floor size on impact sound levels

Effect of floor size on impact sound levels

slackening screws and changing the depth of a resonance. One may conclude from such data that while floor size is an issue, there are other factors that cause results for nominally identical floors to be significantly different. The results for the tire and the walker are similar from the point of view of frequency; the smaller floors show peaks in the response at 50 Hz while the larger floor has a peak around 25 Hz. The peak levels for the tire (although at different frequencies) have about the same amplitude while the levels from the walker are about 10 dB different. A difference of around 20 dB is expected from the simple treatment given above which evidently does not work well with these kinds of floors.
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Effect of MTU length on child-adult difference in neuromuscular fatigue

Effect of MTU length on child-adult difference in neuromuscular fatigue

Muscle oxygenation in the VL was continuously recorded 5 min before and during the entire intermittent fatigue protocol by means of a three-channel, portable continuous-wave NIRS device (PORTAMON, peak wavelengths of 750 nm and 850 nm, Artinis Medical System, Zetten, The Netherlands). Oxygenated, deoxygenated, and total hemoglobin concentration, expressed in micromolars, were calculated from changes in optical density by using a modified Lambert-Beer law for which a differential path length factor is used to correct photon scattering within the tissue (31). The tissue saturation index (TSI), expressed in percent, was also calculated. The TSI corresponds to the oxygenated hemoglobin proportion of total hemoglobin and is derived from the relative absorption coefficients obtained from the slopes of light attenuation at three interoptode distances and by taking the diffusion scattering law into account (32). The NIRS probe was positioned on the VL midway between the lateral epicondyle and the great trochanter of the femur. It was securely strapped to ensure that the probe did not move during the experimental session. An opaque black fabric was placed and fixed over the probe to prevent signal interference by ambient light. The subcutaneous fat layer thicknesses, where the probe was placed, were measured using a B-mode ultrasound (Echo Blaster 128 CEXT-1Z; Telemed, Vilnius, Lithuania) with a 7.5 MHz linear array transducer. Adipose tissue thicknesses over the VL muscle were 6.6 ± 2.5 and 5.8 ± 2.3 mm in boys and men, respectively (P < 0.31). Considering that the adipose tissue thickness was relatively low and the penetration depth of the NIRS signal is more or less half of the emitter-detector distance (4 cm), the changes in signals reflected the muscle hemodynamic changes. NIRS signals were recorded and sampled at 10 Hz using the Oxysoft software (Artinis Medical System, Zetten, The Netherlands).
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Size effect in Quincke rotation: a numerical study

Size effect in Quincke rotation: a numerical study

addressed and it has been shown that both electro-migration and diffusion result in a decrease of the angular velocity of the cylinder and an increase of the threshold field. A modified Quincke model has been proposed to calculate analytically the rotor spin rate. This model accounts for the electro-migration inside the charge layer which is present around the rotor

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Is it worth it? Is an intensive rehabilitation program making a difference for youth with pain-related disability?

Is it worth it? Is an intensive rehabilitation program making a difference for youth with pain-related disability?

Summary Pediatric chronic pain is an important health concern worldwide. Intensive interdisciplinary pain (IIPT) and multimodal treatment (MMT) are the two main service models. Unfortunately, descriptions of these published interventions lack the details necessary to reproduce them in different contexts, and comparison studies between the models are rare. This study had two main objectives: 1) analyse the theoretical foundation of the IIPT program, and 2) analyse the effects of a day-hospital donor funded IIPT compared to those of an outpatient MMT. To evaluate the IIPT theoretical foundation, a 13-member stakeholder advisory group was recruited, and a logic analysis process was used. To evaluate the effects of the IIPT, six outcome domains were prioritized by the same advisory group using a nominal group technique. An effect analysis was then conducted, using a pre-post study design, collecting data on youth participating in an IIPT and those enrolled in an MMT at the same facility. Interviews using a narrative timeline then followed with a subset of youth and parent participants. The results highlighted the sound theoretical foundation of the IIPT. Furthermore, positive effects were demonstrated in youth participating in both the IIPT and MMT, with each treatment revealing advantages and disadvantages. Merging findings and comparing the results provided an opportunity to gain a deeper understanding of what treatments work, and for whom. Some insight into why these treatment options work and suggestions for intervention improvements also emerged. Not only did this study generate the knowledge pivotal to alleviating the suffering and improving the lives of youth with chronic pain and their families in Alberta, in Canada, and beyond, it set a new standard of patient engagement for evaluation research of complex rehabilitation intervention.
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Size effect on the three state thermal hysteresis of a 2D spin crossover nanoparticles

Size effect on the three state thermal hysteresis of a 2D spin crossover nanoparticles

2. Results and discussion Ising Model As a first two-states model, Wajnflasz and Pick [7] introduced the Ising model to describe the spin transition behavior in which only “short-range interaction” between the spin-crossover sites is considered, which means, for a 1D system, the four nearest neighbours. Boussekou et al. [11] made a thorough analysis of this model in the mean field approximation and they reproduce, with a negative short-range interaction, a double step spin transition. Furthermore, Linares et al. [10] introduced a long range interaction in the Hamiltonian besides the short range interaction in order to reproduce hysteresis in 2D compounds. With these contributions, the Hamiltonian include now the short and long range interactions to which we added an energetic contribution “L” [18-20] , « to the ligand-field of edge molecules of a SC nanoparticle ». This term allows us to explicitly take in account the interactions between molecules on the edge and the environment in contact, which weakens the molecules’ field. In this case we can now define the Hamiltonian with the following equation:
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Concussion education : is it making a difference?

Concussion education : is it making a difference?

Abstract In response to the growing concern about concussions, experts have stated a need to educate athletes and members of the sport environment about the injury. Although the type of information that should be included in concussion education has generally been agreed upon (e.g., signs and symptoms, management strategies, long-term sequelae), it is not clear at this point the best way to disseminate this information. Most initiatives have used printed educational materials and web-based platforms such as websites and social networking sites to deliver concussion education. Evidence about the effectiveness of these modalities is currently either inconclusive or has suggested that they are not effective when used as a standalone strategy. There have also been some concussion education interventions published in the literature. Results of the interventions suggests there are short-term improvements in knowledge, but limited effect on knowledge, attitudes, and behaviors beyond three months. This chapter provides an overview of contemporary concussion education efforts and discusses implications for future research and practice.
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Mean Field Games of Controls: Finite Difference Approximations

Mean Field Games of Controls: Finite Difference Approximations

well distributed queue takes place from the entrance to the exit, by contrast with Figure 10 where we see that the agent rush and accumulate in the right part of the domain. Similarly, the deceleration is much stiffer in the latter case. It is not surprising that the interactions through controls have the effect of smoothing the distribution of states and the optimal feedback law. On the bottom of Figure 10, we see that when t is close to the horizon, the distribution is mainly concentrated near the middle of the domain but slightly on the right: this corresponds to the agents that have reached the zone where f 0 has the smaller value, i.e. 1, but for which reaching the exit before T becomes too costly.
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Crack propagation and size effect in concrete using a non-local damage model

Crack propagation and size effect in concrete using a non-local damage model

In this paper, we study crack propagation and size effect in concrete specimens combining some of the above experimen- tal and numerical tools. More specifically, three point bending tests performed at Ecole Centrale Nantes are presented and crack openings are estimated with the DIC technique [10] . An isotropic non-local damage model is used for the numerical simulations and an optimization algorithm is used for the calibration of the material parameters, as suggested in [13] . In addition however, not only global but also local variables (damage distribution and crack opening profiles) are confronted to the experimental results. Parametrical studies are presented and important interesting conclusions are drawn about the ability and limitations of the chosen non-local model to reproduce crack propagation and size effect in concrete specimens.
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On multiplicative update with forgetting factor adaptive step size for least mean-square algorithms

On multiplicative update with forgetting factor adaptive step size for least mean-square algorithms

very beginning of the process) and when the algorithm faces sudden reconfiguration (i.e., when the time-varying channel to be estimated is affected by a sudden change in its model). To improve the efficiency of the transient behavior of the LMS algorithm, many solutions have exploited self-adaptive step size, where the constant step size of the steepest descent is replaced by a variable step size that is tuned according to some criterion that provides a measure of the adaptation process state. The objective is to have a large step size value during the convergence mode, and a small but well-suited value after convergence (i.e closed to the optimal step-size) [16]. The step-size update can be additive or sometimes multiplicative, and the criteria can be based on counting passages through zero (i.e., on sign changes) [17], [18], on square instantaneous error measures [19], [20], or on other statistics that are based on the filtering of the output of the algorithm [21], [7], [22], [23], [24]. Most of these algorithms also limit the step-size evolution, with a maximal value to ensure convergence, and a minimal value (which is strictly positive in the case of multiplicative updates) to conserve reactivity [25], [26]. These methods often offer very good initial convergence speed, but can suffer from a trade-off between a desired reactivity (in the case of reconfigurations) and obtained MSE after convergence. This trade-off can be embodied by introducing the False Alarm Probability (FAP), defined as the probability for the step to quit its minimal value in asymptotic mode. Monitoring the FAP is matter of importance as false alarms lead to excess MSE, and thus loss of performance. This is particularly the case with additive updates such that the return time (i.e., the time for the step to re-converge after a reconfiguration to its minimal value, which is regarded as an equilibrium) is longer than with multiplicative updates [27].
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A remark on Uzawa's algorithm and an application to mean field games systems

A remark on Uzawa's algorithm and an application to mean field games systems

Uzawa’s algorithm was introduced to solve minimization problems with con- straints. The main idea of this algorithm is to use a projected gradient descent on the dual problem. Because of its simplicity and efficiency, Uzawa’s algorithm is often used in practical problems. We recall that the output of this algorithm is a sequence which converges toward the solution of the primal minimization problem. In the first part of this paper we prove that we can use the same algorithm to find solutions of a wider class of systems than the ones which characterize saddle points of lagrangians.
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