Search results for "Goodness of fit"
showing 10 items of 54 documents
A Methodology to Derive Global Maps of Leaf Traits Using Remote Sensing and Climate Data
2018
This paper introduces a modular processing chain to derive global high-resolution maps of leaf traits. In particular, we present global maps at 500 m resolution of specific leaf area, leaf dry matter content, leaf nitrogen and phosphorus content per dry mass, and leaf nitrogen/phosphorus ratio. The processing chain exploits machine learning techniques along with optical remote sensing data (MODIS/Landsat) and climate data for gap filling and up-scaling of in-situ measured leaf traits. The chain first uses random forests regression with surrogates to fill gaps in the database (> 45% of missing entries) and maximizes the global representativeness of the trait dataset. Plant species are then a…
Validation of a Short Form of Job Crafting Scale in a Spanish Sample
2018
AbstractApplications of job crafting are widespread in the professional practice. In an attempt to measure this phenomenon, Tims, Bakker and Derks (2012) developed a Job Crafting Scale based on the Job Demand-Resources model (JD-R) and validated it in a Dutch sample. However, its application to other cultural contexts presented some difficulties. The present work aimed to validate a shorter version of scale by Tims et al. (2012) in a Spanish sample (n = 1,647). The data were randomly split in two independent subsamples (Sample 1: Explorative; Sample 2: Confirmative). The exploratory factor analysis showed a three-factor structure. Through a confirmatory factor analysis, the four-dimensional…
The Factorial Structure of the Outcome Questionnaire-45: A Study with an Italian Sample.
2008
In this article, the authors study the factorial structure of the Italian translation of the Outcome Questionnaire 45 (OQ-45) in a sample of college students (n = 522) and psychiatric outpatients (n = 301). The relative goodness of fit of six competing models of the OQ-45 was examined using confirmatory factor analysis (CFA). Specifically, the study examined the relative fit of the most frequently presented models in the literature and three alternative models. Results of the CFA provided support for the four factor bi-level solution, suggesting that the OQ-45 is a multidimensional instrument that contains one general factor and multiple unique subscale factors.
Neural Network for Estimating Energy Expenditure in Paraplegics from Heart Rate
2014
The aim of the present study is to obtain models for estimating energy expenditure based on the heart rates of people with spinal cord injury without requiring individual calibration. A cohort of 20 persons with spinal cord injury performed a routine of 10 activities while their breath-by-breath oxygen consumption and heart rates were monitored. The minute-by-minute oxygen consumption collected from minute 4 to minute 7 was used as the dependent variable. A total of 7 features extracted from the heart rate signals were used as independent variables. 2 mathematical models were used to estimate the oxygen consumption using the heart rate: a multiple linear model and artificial neural networks…
Design of measurement-based correlation models for shadow fading
2010
This paper deals with the design of measurement-based correlation models for shadow fading. Based on the correlation model, we design a simulation model using the sumof-sinusoids (SOS) method to enable the simulation of spatial lognormal processes characterizing real-world shadow fading scenarios. The model parameters of the simulation model are computed by applying the L p -norm method (LPNM). This method facilitates an excellent fitting of the simulation model's autocorrelation function (ACF) to that of measured channels. Our study includes an evaluation of all important statistical quantities of the proposed measurement-based simulation model, such as the probability density function (PD…
Competing factor structures of the Rosenberg Self-Esteem Scale (RSES) and its measurement invariance across clinical and non-clinical samples
2017
Abstract Although several studies have investigated the factor structure of the Rosenberg Self-Esteem Scale (RSES), there are still disagreements about it. The present study assessed: a) the goodness of fit of nine competing factor models for the RSES using data from a clinical sample of 855 women with eating/weight disorders; and b) its measurement invariance across clinical and non-clinical (n = 943) samples. A bifactor model, with a general self-esteem factor, plus positive and negative method factors, provided a better fit with the data than alternative models. However, the results showed the high reliability of the general self-esteem factor, and a low reliability of the two method fac…
Calculation of chromatographic parameters by molecular topology: sulphamides
1994
This investigation was undertaken to test the ability of the molecular connectivity model to predict RF values in thin-layer chromatography (TLC) for a group of sulphamides using multi-variable regression equations with multiple correlation coefficients, standard error of estimate, F-Snedecor function values and Student's t-test as criteria of fit. Regression analyses showed that the molecular connectivity model predicts the values for this property in different silica gel stationary phases and different polar mobile phases. Corresponding stability and random studies were made on the selected prediction models which confirmed their goodness of fit. The results also demonstrated that differe…
Testing Motivacional theories in Music Education: the role of Effort and Gratitude
2019
Acquiring musical skills requires sustained effort over long periods of time. This work aims to explore the variables involved in sustaining motivation in music students, including perceptions about one’s own skills, satisfaction with achievements, effort, the importance of music in one’s life, and perception of the sacrifice made. Two models were developed in which the variable of gratitude was included to integrate positive psychology into the motivational area of music education. The first predicts effort, while the second predicts gratitude. The models were tested using a sample of 84 music students. Both models were fitted using Bayesian analysis techniques to examine the relationship …
Automatic regrouping of strata in the goodness-of-fit chi-square test
2019
Pearson’s chi-square test is widely employed in social and health sciences to analyze categorical data and contingency tables. For the test to be valid, the sample size must be large enough to provide a minimum number of expected elements per category. This paper develops functions for regrouping strata automatically no matter where they are located, thus enabling the goodness-of-fit test to be performed within an iterative procedure. The functions are written in Excel VBA (Visual Basic for Applications) and in Mathematica. The usefulness and performance of these functions is illustrated by means of a simulation study and the application to different datasets. Finally, the iterative use of …
Interpretation of Ocular Melanin Drug Binding Assays. Alternatives to the Model of Multiple Classes of Independent Sites
2016
Melanin has a high binding affinity for a wide range of drugs. The determination of the melanin binding capacity and its binding affinity are important, e.g., in the determination of the ocular drug distribution, the prediction of drug effects in the eye, and the trans-scleral drug delivery. The binding parameters estimated from a given data set vary significantly when using different isotherms or different nonlinear fitting methods. In this work, the commonly used bi-Langmuir isotherm, which assumes two classes of independent sites, is confronted with the Sips isotherm. Direct, log-log, and Scatchard plots are used, and the interpretation of the binding curves in the latter is critically a…