Search results for "Sample"
showing 10 items of 2270 documents
Revenue models, in-app purchase, and the app performance: Evidence from Apple's App Store and Google Play
2016
The effect of revenue models on app performance depends on the app store.The effect of in-app purchase on app performance depends on the app store.Paid, freemium and in-purchase models are shown to be effective in app store.Freemium and in-app purchase models are shown to be less effective in Google Play.App category influences the effects of both revenue models and in-app purchase. In this paper, we empirically examine how the revenue model (paid, free, or freemium) adopted for a given app affects the app revenue performance as measured by the app daily revenue rank. We also study the impact of in-app purchase on this measure of performance. Moreover, we study how such relationships are co…
Sample Preparation to Determine Pharmaceutical and Personal Care Products in an All-Water Matrix: Solid Phase Extraction
2020
© 2020 by the authors.
Speeding up of microstructure reconstruction: II. Application to patterns of poly-dispersed islands
2015
We report a fast, efficient and credible statistical reconstruction of any two-phase patterns of islands of miscellaneous shapes and poly-dispersed in sizes. In the proposed multi-scale approach called a weighted doubly-hybrid, two different pairs of hybrid descriptors are used. As the first pair, we employ entropic quantifiers, while correlation functions are the second pair. Their competition allows considering a wider spectrum of morphological features. Instead of a standard random initial configuration, a synthetic one with the same number of islands as that of the target is created by a cellular automaton. This is the key point for speeding-up of microstructure reconstruction, making u…
Perceived statistical knowledge level and self-reported statistical practice among academic psychologists
2018
Introduction: Publications arguing against the null hypothesis significance testing (NHST) procedure and in favor of good statistical practices have increased. The most frequently mentioned alternatives to NHST are effect size statistics (ES), confidence intervals (CIs), and meta-analyses. A recent survey conducted in Spain found that academic psychologists have poor knowledge about effect size statistics, confidence intervals, and graphic displays for meta-analyses, which might lead to a misinterpretation of the results. In addition, it also found that, although the use of ES is becoming generalized, the same thing is not true for CIs. Finally, academics with greater knowledge about ES sta…
Assessing farming eco-efficiency: a Data Envelopment Analysis approach.
2010
This paper assesses farming eco-efficiency using Data Envelopment Analysis (DEA) techniques. Eco-efficiency scores at both farm and environmental pressure-specific levels are computed for a sample of Spanish farmers operating in the rain-fed agricultural system of Campos County. The determinants of eco-efficiency are then studied using truncated regression and bootstrapping techniques. We contribute to previous literature in this field of research by including information on slacks in the assessment of the potential environmental pressure reductions in a DEA framework. Our results reveal that farmers are quite eco-inefficient, with very few differences emerging among specific environmental …
Flexible Estimation of Heteroskedastic Stochastic Frontier Models via Two-step Iterative Nonlinear Least Squares
2019
Despite its importance, the monotonicity condition is typically overlooked in stochastic frontier analysis. This article illustrates a straightforward and useful method for the estimation of semiparametric stochastic frontier models imposing such constraint and incorporating exogenous inefficiency effects exploiting the scaling property. An iterative estimation algorithm based on nonlinear least squares is developed and the behavior of the proposed procedure is investigated through a set of Monte Carlo experiments comparing its finite sample properties with those of available alternatives. The simulation results highlight very good performance of the new algorithm which outperforms the comp…
Government consumption volatility and the size of nations
2016
This paper analyzes the relation between government consumption volatility and country size. Using an unbalanced sample of 160 countries from 1960 to 2010, it finds that smaller countries have more volatile government consumption. Moreover, while this relation is more negative for more volatile economies, there is also evidence that smaller countries have more volatile government consumption even controlling for the level of volatility in the economy.
Assessing eco-efficiency with directional distance functions
2012
Abstract Eco-efficiency is a matter of concern at present that is receiving increasing attention in political, academic and business circles. Broadly speaking, this concept refers to the ability to create more goods and services with less impact on the environment and less consumption of natural resources, thus involving both economic and also ecological issues. In this paper we propose the use of directional distance functions and Data Envelopment Analysis techniques to assess eco-efficiency. More specifically, we show how these functions can be used to compute a wide range of indicators representing different objectives regarding economic and ecological performance. This methodological ap…
Is there a link between BMI and depressive symptomatology, risky consumption of alcohol and anxious symptomatology? Study in a sample of university s…
2019
BACKGROUND: One of the often-underestimated aspects of obesity is the psychological one. In particular, there is a growing attention to the correlation between obesity and depression among students from all over the world. And also towards the correlation between alcohol abuse and mood disorders. The objective of the study was to examine if the depressive symptomatology, risk of consumption of alcohol and anxiety symptomatology are correlated with obesity/ overweight in a sample of students of the University of Palermo, Italy. METHODS: The study was a cross-sectional study. A questionnaire is structured in four sections. An anonymous online survey was sent to a random students sample enroll…
Segmentación del turista deportivo: el caso del espectador de la Fórmula 1
2021
El trabajo pretende identificar grupos de turistas de un evento deportivo, el GP Europa de Fórmula 1, con relación a su motivación para el consumo deportivo y características básicas que definen dichos grupos para conocer los perfiles de turista de un gran evento deportivo. Para caracterizar a los sujetos se utilizó el análisis clúster con una muestra de 148 asistentes al evento, turistas nacionales e internacionales. Los resultados obtenidos muestran la existencia de cuatro grupos de sujetos bien definidos: los sociales (formado por los que obtienen fuertes connotaciones sociales asistiendo al evento, el 17,6% de la muestra), los ostentosos (son el 17,5% de la muestra, que sin una motivaci…