Search results for "variance"
showing 10 items of 2030 documents
Power Profiles and In Vitro Optical Quality of Scleral Contact Lenses: Effect of the Aperture and Power
2017
To assess the power profile and in vitro optical quality of scleral contact lenses with different powers as a function of the optical aperture. The mini and semiscleral contact lenses (Procornea) were measured for five powers per design. The NIMO TR-1504 (Lambda-X) was used to assess the power profile and Zernike coefficients of each contact lens. Ten measurements per lens were taken at 3- and 6-mm apertures. Furthermore, the optical quality of each lens was described in Zernike coefficients, modulation transfer function, and point spread function (PSF). A convolution of each lens PSF with an eye-chart image was also computed. The optical power fluctuated less than 0.5 diopters (D) along th…
Retrieving Quantum Information with Active Learning
2019
Active learning is a machine learning method aiming at optimal design for model training. At variance with supervised learning, which labels all samples, active learning provides an improved model by labeling samples with maximal uncertainty according to the estimation model. Here, we propose the use of active learning for efficient quantum information retrieval, which is a crucial task in the design of quantum experiments. Meanwhile, when dealing with large data output, we employ active learning for the sake of classification with minimal cost in fidelity loss. Indeed, labeling only 5% samples, we achieve almost 90% rate estimation. The introduction of active learning methods in the data a…
Study Approaches in Higher Education Mathematics : Investigating the Statistical Behaviour of an Instrument Translated into Norwegian
2019
The revised two-factor study process questionnaire (R-SPQ-2F) has widely been considered valid and reliable in many contexts for measuring students&rsquo
Coping with Burnout Symptoms through Task Significance in Professionals Working with Individuals with Intellectual Disability
2021
ABSTRACT This study examined an intervention that links task significance (one’s job has a positive impact on other people) to burnout symptoms of professionals working in organizations for individuals with intellectual disability. Professionals assigned to the experimental condition participated in teams designed to enhance the positive impact of their work on others (task significance). To do so, teams focused on a task to improve the quality of life of individuals with intellectual disability. Professionals assigned to the control condition did not participate in these teams, and they continued with their usual work. All the participating professionals answered a questionnaire abou…
Employment sector and pay gaps: Genetic and environmental influences
2012
This paper examines the role of genetic factors and shared environment in explaining the choice of working in the public sector and public-private sector pay gaps. The analyses are done using data for Finnish twins that span the period from 1990 to 2004. The data are based on two sources. The first data are Finnish Twin Cohort conducted by Department of Public Health in University of Helsinki. These data have been matched with the Finnish Longitudinal Employer-Employee Data (FLEED) kept by Statistics Finland. The standard behavioural genetics decomposition and DF (DeFries and Fulker 1985) analyses indicate that public sector employment is broadly influenced by the genetic factors by around …
Correlation, hierarchies, and networks in financial markets
2010
We discuss some methods to quantitatively investigate the properties of correlation matrices. Correlation matrices play an important role in portfolio optimization and in several other quantitative descriptions of asset price dynamics in financial markets. Specifically, we discuss how to define and obtain hierarchical trees, correlation based trees and networks from a correlation matrix. The hierarchical clustering and other procedures performed on the correlation matrix to detect statistically reliable aspects of the correlation matrix are seen as filtering procedures of the correlation matrix. We also discuss a method to associate a hierarchically nested factor model to a hierarchical tre…
El viaje desde los cuestionarios Likert a los cuestionarios de elección forzosa: evidencia de la invarianza de los parámetros de los ítems
2019
Multidimensional forced-choice questionnaires are widely regarded in the personnel selection literature for their ability to control response biases. Recently developed IRT models usually rely on the assumption that item parameters remain invariant when they are paired in forced-choice blocks, without giving it much consideration. This study aims to test this assumption empirically on the MUPP-2PL model, comparing the parameter estimates of the forced-choice format to their graded-scale equivalent on a Big Five personality instrument. The assumption was found to hold reasonably well, especially for the discrimination parameters. In the cases in which it was violated, we briefly discuss the …
Testing invariance between web and paper students satisfaction surveys. A case study
2017
[EN] Purpose: This paper studied the measurement invariance (MI) across web-based and paper-based surveys to evidence if both techniques of data collection can be regarded as equivalent. Design/methodology: We develop a multigroup confirmatory factor analysis (MGCFA) with Maximum Likelihood Estimation to asses measurement invariance of the Job Diagnostic Survey (JDS) adapted to teaching, with data collected from paper and web surveys. Sample from paper surveys was constituted by 294 student of a Spanish public university in the academic years 2007-08, 2008-09 and 2009-10. Internet surveys were administered through an open source survey application called Lime Survey. We received 241 complet…
Teacher stress during a school year: Covariance and mean structure analyses
1989
This study examined teacher stress over a school year. A total of 142 teachers made repeated assessments (12 in all) of the stress indicators by answering questionnaires during the school year of 1983–1984. Longitudinal quasi-simplex models and modifications of these were constructed for the analysis of the structural features of the teacher stress process over a school year. By using these models all the stress data could be analysed at the same time in a statistically efficient way. According to the constructed models, teacher stress was a stable process during terms, which meant that the variance in latent stress in the measurements was well explained by the previous measurement. The Chr…
Hyoid bone position in different facial skeletal patterns
2018
Background Hyoid bone plays a significant role in physiological functions of craniofacial region and it’s position adapts to changes of the head. The purpose of this study was to determine the position of the hyoid bone among subjects with class I, class II and class III skeletal patterns and evaluate the gender differences. Material and Methods One hundred and ten lateral cephalograms (59 females and 51 males) from different skeletal patterns (class I, II and III) were selected. The skeletal patterns were determined according to ANB angle. Using MicroDicom software, different linear and angular measurements (6 variables) was carried out to determine the position of hyoid bone. Intraclass c…