Search results for "arima"
showing 10 items of 40 documents
Use of an artificial model of monitoring data to aid interpretation of principal component analysis
2000
Abstract An artificial data matrix of element concentrations at sampling locations was created which included six simulated gradients of correlated variables (Ca+Mg, Ni+V, Pb+Cu+Zn, Cd, Fe and K), representing a simplified model of a National survey. The data matrix model was used to explore the efficiency with which Principal Components Analysis (PCA), without and with Varimax rotation, could derive the imposed gradients. The dependence of PCA on outliers was decreased by log-transformation of data. The Components derived from non-rotated PCA were confounded by bipolar clusters and oblique gradients, both resulting in superimposition of two independent gradients on one Component. Therefore…
Validez factorial de la adaptación al español del Maslach Burnout Inventory-General Survey
2002
Objective. To explore the factorial structure of a Spanish version of the “Maslach Burnout Inventory-General Survey” (MBI-GS). Material and Methods. A cross-sectional study was conducted in 1999 among 149 municipal policemen in Tenerife, Spain. A questionnaire was applied to collect data on Professional Efficacy, Cynicism, and Burnout. Data were analyzed using factorial analysis and principal components with Varimax rotation. Results. Four factors had eigenvalues greater than 1; Factor 1 gouped Professional Efficacy items, Factor II grouped three Cynicism items. Further analysis was conducted to limit extraction to three factors. The factorial solution replicated the distribution of items i…
Laika rindu analīzes metodes akciju cenu prognozēšanā
2020
Bakalaura darba mērķis izpētīt laika rindu analīzes metožu pielietojuma iespējas akciju cenu analīzē un prognozēšanā, kā arī novērtēt dažāda veida modeļu izmantošanas potenciālu konkrēta uzņēmuma akciju cenu prognozēšanā. Darbā sniegts laika rindu analīzes un prognozēšanas metožu pārskats, laika rindu prognozēšanas problēmu situāciju izpēte. Apskatītās metodes kā ARIMA, ARIMAX, SARIMAX un VAR tika pielietotas uzņēmuma Volkswagen akciju cenu prognozēšanā, izmantojot datus par 2009. – 2019. gadu laika periodu. Lai ņemtu vērā kopējā tirgus tendences, modeļi tika papildināti ar diviem eksogēniem mainīgiem – uzņēmuma Porsche un uzņēmuma BMW akciju cenām par iepriekš minēto periodu. Prognozēšanas…
L'ensenyament del català a la ràdio durant el tardofranquisme : 'cursos de catalán' (1969) de Ràdio Barcelona
2018
En el context dels intents de recuperació de l'ensenyament del català que van succeir-se durant la dècada dels seixanta, el 1969 Ràdio Barcelona va posar en antena el programa Cursos de catalán, ideat i escrit pel poeta, gramàtic i editor Miquel Arimany, al qual posaven veu ell mateix i els locutors Isidre Sola, Enriqueta Teixidó i Xavier Ubach, dirigits per Armand Blanch. El programa, que es va estroncar a la trenta-tresena emissió, tenia com a objectiu fonamental l'extensió del coneixement del català entre el col·lectiu immigrant, condició imprescindible per a eixamplar-ne l'ús. El present article analitza les característiques del curs: l'alternança de castellà i català com a llengües veh…
Use of the Perceived Physical Competence Scale with Adolescents with Disabilities
1995
The construct validity and reliability of the 1987 Perceived Physical Competence Scale of Lintunen were examined to assess the applicability of the instrument for use with adolescents with disabilities. Subjects were 51 girls and 34 boys ( M age = 15.1 yr.) from several schools in central Finland. Principal component factor analysis with varimax rotation yielded the same two factors for adolescents with disabilities as reported for nondisabled adolescents in the related literature. Cronbach alphas for the two factors were .89 and .56. It was concluded that the scale is an appropriate measure for adolescents with disabilities. Statistical analysis indicated no gender differences for adolesc…
Testing and using Goldberg's General Health Questionnaire: Mental health in relation to home nursing, home help, and family care among older, care-de…
2009
The aims of this study were to test the Norwegian version of Goldberg's 30-item General Health Questionnaire (GHQ-30) in a group of older, care-dependent individuals living at home; to describe self-reported mental health; and to relate mental health to receiving home nursing, home help, and family care. A sample of 234 home nursing patients in Norway aged 75 years and older was interviewed. Mental state was assessed using the GHQ-30. Reliability and validity were calculated with Spearman's rank correlations, Cronbach's alpha coefficient, and Mann-Whitney U-test. The factor analysis was performed using the principal components analysis with varimax rotation and Kaiser normalization. Demogra…
Multivariate factor analysis of Girgentana goat milk composition
2005
The interpretation of the several variables that contribute to defining milk quality is difficult due to the high degree of correlation among them. In this case, one of the best methods of statistical processing is factor analysis, which belongs to the multivariate groups; for our study this particular statistical approach was employed. A total of 1485 individual goat milk samples from 117 Girgentana goats, were collected fortnightly from January to July, and analysed for physical and chemical composition, and clotting properties. Milk pH and tritable acidity were within the normal range for fresh goat milk. Morning milk yield resulted 704 ± 323 g with 3.93 ± 1.23% and 3.…
Improving the prediction of air pollution peak episodes generated by urban transport networks
2016
Abstract This paper illustrates the early results of ongoing research developing novel methods to analyse and simulate the relationship between trasport-related air pollutant concentrations and easily accessible explanatory variables. The final scope is to integrate the new models in traditional traffic management support systems for a sustainable mobility of road vehicles in urban areas. This first stage concerns the relationship between the hourly mean concentration of nitrogen dioxide (NO2) and explanatory factors reflecting the NO2 mean level one hour back, along with traffic and weather conditions. Particular attention is given to the prediction of pollution peaks, defined as exceedanc…
A Survey of Teacher Perceptions of the School Psychologist's Skills in the Consultation Process An Exploratory Factor Analysis
2004
The main purpose of this study is to present the construction and validation process of an instrument designed to evaluate the professional skills of the school psychologist in the teacher consultation process. Initially, an extensive list of items was created which evaluated the characteristics of school psychologists in this area. After carrying out a pilot study and making the necessary modi.cations, we presented the scale to a sample of 157 primary and secondary public school teachers in the Valencian Community. An exploratory factor analysis was carried out on the main components, applying the corresponding varimax rotation. The results show a factorial structure made up of three comp…
Transcultural adaptation and validation of the spanish version of the sexual satisfaction scale for women (SSS-W-E)
2021
Background: Sexual satisfaction is a complex and multidimensional concept. It encompasses physical, emotional, relational and cultural dimensions, and constitutes an essential component of sexual health, as well as an indicator of quality of life and wellbeing. The Sexual Satisfaction Scale for Women (SSS-W) was designed in the United States, and it is a valid and reliable tool to measure women’s sexual satisfaction. Aim: The aim of this study was to culturally adapt and translate the SSS-W into Spanish and analyze its psychometric properties. Methods: First, the original instrument was culturally adapted and translated from English to Spanish. Then, we tested the psychometric properties of…