79 resultados para Análise de regressão múltipla
em Universidade Federal do Rio Grande do Norte(UFRN)
Resumo:
Telecommunication is one of the most dynamic and strategic areas in the world. Many technological innovations has modified the way information is exchanged. Information and knowledge are now shared in networks. Broadband Internet is the new way of sharing contents and information. This dissertation deals with performance indicators related to maintenance services of telecommunications networks and uses models of multivariate regression to estimate churn, which is the loss of customers to other companies. In a competitive environment, telecommunications companies have devised strategies to minimize the loss of customers. Loosing customers presents a higher cost than obtaining new ones. Corporations have plenty of data stored in a diversity of databases. Usually the data are not explored properly. This work uses the Knowledge Discovery in Databases (KDD) to establish rules and new models to explain how churn, as a dependent variable, are related to a diversity of service indicators, such as time to deploy the service (in hours), time to repair (in hours), and so on. Extraction of meaningful knowledge is, in many cases, a challenge. Models were tested and statistically analyzed. The work also shows results that allows the analysis and identification of which quality services indicators influence the churn. Actions are also proposed to solve, at least in part, this problem
Resumo:
The kinanthropometric characteristics are used by the sports science as selection criteria and detection of talents. Hence, this study aimed at comparing the anthropometrical profile, the body composition, the somatotype and the vertical jumps of the beach volleyball players. This study consists of 79 male beach volleyball players, being forty nine (n=49) Brazilian participants of the National Circuit and thirty (n=30) of 15 countries participating in the XV Pan American Games. In order to analyze the vertical jumps of the Brazilian the participants were allocated into two groups (G1 and G2) in agreement with the national ranking of their teams. The vertical jump protocol developed by Smith and collaborators was used to evaluate the vertical jumps of spike and block. The Heath-Carter anthropometrical technique (1990) was used for calculating the somatotype. The Student s t test with the Bonferroni adjustment was used to calculate the differences among the investigated variables. The multiple regression analysis was used to identify the contributions of the anthropometrical variables in the performance of the vertical jumps and the multivariance analysis was used to calculate the differences among the components of the somatotype. The Brazilian athletes of G1 were better than G2 in the spike jump (p <0.01), block jump (p <0.01) and in the block difference (p <0.01). The prediction model of the spike jump of G2 included the body mass and standing spike reach (adjusted R2 = 0.77), the body mass and the standing block reach were also included in the model of the block jump (adjusted R2 = 0.73). The regression model of G1 was not statistically significant. As for the somatotype, statistically significant differences were found between the Brazilians and the Pan Americans (Wilks' lambda = 0.498; p <0.05). The Brazilian somatotype was classified as balanced mesomorph (2.7-4.3-3.0) and the Pan American somatotype as endomorphic mesomorph (3.5-4.6-2.4). As to the specific position of the block game (2.8-4.3-2.9) and the defense game (2.6-4.4-3.0), the Brazilian somatotype was classified as balanced mesomorph and the Pan American somatotype, the block (3.7-4.4-2.4) and the defense (3.4-4.9-2.3), was classified as endomorphic mesomorph. In conclusion, the vertical jump height (spike and block) influences the male Brazilian beach volleyball players performance. The physical type of the Brazilian blockers and defenders was similar with relationship to the somatotype. The Brazilian and Pan American beach volleyball players differ in terms of kinanthropometric characteristics. This work had a multidisciplinary feature with the participation of several departments and laboratories, like the Physiotherapy Department, the Nutrition Department, the Physical Education Laboratory, thus corroborating the multidisciplinary research feature
Resumo:
The use of animals is a common activity but it can be really variable between human populations. This work analyzed the knowledge about useful animal species between human communities in Caatinga and Atlantic Forest considering the influence of socioeconomics and environmental factors on the species selection. Forty people were interviewed in Caraúbas community (Atlantic Forest) and thirty were interviewed in Barrocas community (Caatinga). A total of 193 animals were cited. The communities showed a low degree of similarity (20%) and the general diversity of mentioned species was significantly bigger in Caraúbas. Men cited a diversity of species greater than women for food category in Caraúbas and pet category in Caraúbas and Barrocas. Women cited greater species diversity for medicinal use in Caraúbas. In general, in both communities, the age group >60 years showed a greater knowledge than the others. The multiple regression analysis showed the age as the only socioeconomic factor which influenced significantly the knowledge about animals for the food category in both communities. Considering the richness of known species, there were differences only between gender for sum of uses and food category in Caraúbas and for the pet category in Barrocas with men showing a greater knowledge than women. The results showed that local environmental differences are fundamental at the species selection but they also showed that within communities there are other factors like gender and age that tend to influence the knowledge about species. It is important to consider cultural, economic, social and environmental factors to understand better the interactions between people and animals so that this information can be used to facilitate the implementation of conservation measures
Resumo:
This thesis deals with the factors affecting customer satisfaction, loyalty and recommendation in the health care sector. It is adapted a model proposed by Johnson et al. (2001) of quality and loyalty antecedent factors and it is conducted a survey with a sample of 109 customers of a hospital on the ambulatory in Natal city, a capital of a Northeastern State of Brazil. It is carried descriptive and multiple regression statistical analysis. The main findings related to satisfaction are that quality factors of doctor professionalism, clerical staff efficiency, consultancy room comfort, time to provide the medical consultancy but also hospital localization are the most significant factors affecting satisfaction. Regarding personal full loyalty, satisfaction with the hospital and affective commitment are the main factors yet for partial loyalty image and calculate commitment play the main role. For recommendation satisfaction, image and brand are the main factors. The overall model used fairly explains the satisfaction, loyalty and recommendation outcomes with varying factors regarding each final purpose, e.g. loyalty or recommendation
Resumo:
The objective of this thesis was studying the factors which contribute to customer s satisfaction and loyalty, focusing the Norwegian model of satisfaction and loyalty of the consumer, applied in the sector of hotel services in Natal/RN, Brazil. The theoretical research was led through the concepts of service quality, customer satisfaction and loyalty, models of quality management systems, national index of customer s satisfaction and methods which evaluate the customer s satisfaction. The field research was carried through from December 1st of 2004 to 24 st, among 381 international tourists who had been housed in the hotels of Natal. The analyses of the data had been made through the descriptive statistics and analysis of multiple regression. The results had evidenced that the main precedents variables of satisfaction had been: hotel s room, staff friendliness, hotel restaurant food and price paid; these are factors which explained, in 56,0% the variation of satisfaction with hotels. In relation to the constructs which had influenced the tourist s loyalty, were founds: tourist s satisfaction, hotel image and affective commitment, which had explained 53.0% of the data variability. The complaint management resulted as a basic factor for the tourist s satisfaction and loyalty
Resumo:
This Thesis deals with a study on customer satisfaction and loyalty measurement focusing on a model of factors antecedents of customer satisfaction and loyalty. The model is based on a Satisfaction Index model adopted in Norway developed by Johnson et al.(2001) and the service quality drivers from the literature. It is surveyed a sample of 130 patients of a gynecology clinical. It is used a multiple regression analysis as the main statistical method in order to verify the factors affecting satisfaction and loyalty. The main findings are that the quality model explain 54% of the satisfaction but the whole model explain only 31% of the loyalty. Although the results are consistent with the literature in term of quality as the main driver of the satisfaction and that the satisfaction is not only one factor to explain loyalty, both the quality model to satisfaction and the factors model affecting loyalty should be improved to explain better the satisfaction and loyalty in health care service
Resumo:
This Master of Science Thesis deals with the customer satisfaction and loyalty focusing on a private higher education institution in Belém city, Brazil. The literature review focuses on costumer satisfaction and loyalty concepts and theory, models of quality managing systems and methodologies of costumer satisfaction measurement. The research was a survey with a random stratified sample of 329 undergraduate students of Business Administration at the Faculdade do Pará , in the morning and the night periods. The data analysis was made through the descriptive statistics and multiple regression analysis. The main findings are that the model was satisfactory and the main factors affecting Satisfaction to the School were Best Professor Didatics (beta=0.297), Courses Contents (beta=0.280), Clerks Sympathy (beta=0.201), and Number of Students in Classroom (beta=0,187) with a adjusted R2 = 0,47. The main factors affecting School Loyalty with an adjusted R2 = 0,43 were School Image (beta=0.383), Affective Commitment (beta=0.255), and Satisfaction with Professors (beta=0,218). The findings suggest also that may be differences between the set of students and those that complain for something
Resumo:
This thesis deals with the factors affecting customer satisfaction and loyalty in the mobile phone telecom sector. It is adapted a model proposed by Johnson et al. (2001) of quality and loyalty antecedent factors. It is conducted a survey with a sample of 385 customers of mobile phone telecom sector in Teresina city, a capital of a Northeastern State of Brazil, and descriptives and multiple regression statistical analysis. The main findings related to satisfaction are that quality and service price are the significant factors affecting it. Regarding loyalty, satisfaction, image, affective commitment, and calculate commitment are the significant factors to explain it. The overall model used fairly explain the satisfaction and loyalty outcomes
Resumo:
This Thesis deals with a study on customer satisfaction and loyalty focusing on a model of factors antecedents of customer satisfaction and loyalty. The model is based on a Satisfaction Index model adopted in Norway developed by Johnson et al.(2001) and the service quality drivers from the literature. It is surveyed a sample of tourist in Natal. It is used a survey questionnaire applied at the airport in the departure moment of the tourist. The final sample results on 198 cases. Is is used a multiple regression analysis as the method to verify the factor affecting satisfaction and loyalty. Two models arise from the analysis. The first model concerning satisfaction results with cleaness and hygiene of the bathroom, leisure facilities, employees promptness, and price as the significant factors affecting satisfaction. The model has a R2 of 0.6430 and the also check in service, cleaness of the apartment and the hotel in general, bedroom setting have colinearity with some factors entering the model. The loyalty model results with satisfaction, affective commitment as the main factors affecting loyalty, with a R2 0.5396, and also image has collinearity with satisfaction. A small part of the sample has complained and this factor was not considered in the models. The results are consistent with the literature in term of quality as the main driver of the satisfaction and that it is not the only one factor to explain loyalty
Resumo:
The organic products represent one of the main trends of alimentary consumption in the new century. In Brazil, the answer is already well representative which it becomes the country, as a great consuming and exporting market of products of LVF type. The objective of this research was to investigate the factors capable to influence the food consumer in its purchase decision of organic products in the supermarkets of Teresina, capital of Piauí State. The methodology was exploratory and descriptive, using survey, with closed and opened questions in 542 interviewed. The questionnaire was based on projected scales to evaluate the factors that can influence the purchase decision of organic products, whose variable had been grouped in the following groups: behavior, knowledge, interest, competitiveness, importance, barrier and profile. The used statistical techniques were descriptive analysis and multiple regression analysis. The results demonstrate interest of the population in paying more for the organic product, due to better quality of life, however it lacks to one better spreading and greater sensitization to attract these consumers. Some recommendations and proposals are presented after the results, as suggestions for future research
Resumo:
This Master s thesis presents a discussion on customer satisfaction models investigating the relations of antecedent variables service quality, price index, complaint handling, image, affective and calculative commitment, with satisfaction and loyalty. The scope of the research is the influence of service dimensions in the car buyer s satisfaction and loyalty. A sample of 91 customers was surveyed among new cars buyers of one brand in Natal city, Brazil, and the data was analyzed using multiple regression analysis. The literature review covers subjects such as customer satisfaction, management system, customer satisfaction measurement index models. The main findings suggest that satisfaction with the car brand is mainly influenced by customization of the service, time for accomplishing servicing, and the way the dealer handle complains. Regarding the dealer itself the main variable related to satisfaction is also time for accomplishing servicing. Considering customer loyalty, the customer satisfaction with the dealer explain strongly the loyalty with the brand/manufacturer. Also, the satisfaction, affective commitment and complains handling were found related to loyalty, as the stronger variables explaining the loyalty variance. One main conclusion is that service provided by dealers is one key factor influencing the customer satisfaction and loyalty in auto industry
Resumo:
Background: Obesity impairment to the pulmonary function related to the magnitude of adiposity and is associated with excessive daytime sleepiness (EDS) and snoring, among others symptoms of respiratory disorders related to sleep. It is possible that obese individuals with excessive daytime sleepiness may make changes in lung function on spirometry monitored during the day as a consequence of fragmented sleep or episodes of nocturnal hypoventilation that cause respiratory and changes that can persist throughout the day. The combination of these findings alone sleepiness observed by subjective scales with pulmonary function in obese patients is unknown. Objective: To assess the influence of EDS and snoring on pulmonary function in morbidly obese and distinguish between different anthropometric markers, the snoring and sleepiness which the best predictors of spirometric function and respiratory muscle strength and endurance of these patients. Methods: We evaluated 40 morbidly obese markers on the anthropometric, spirometric respiratory variables, maximal inspiratory and expiratory pressures (MIP and MEP) and maximal voluntary ventilation (MVV) and the measured excessive daytime sleepiness (the Epworth sleepiness scale) and snoring (snoring scale of Stanford). The data were treated when the differences between the groups of obese patients with and without sleepiness, whereas the anthropometric variables, respiratory and snoring. Pearson's correlation was performed, and multiple regression analysis assessed the predictors of pulmonary function. For this we used the software SPSS 15.0 for windows and p <0.05. Results: 39 obese patients were included (28 women), age 36.92+11.97y, body mass index (BMI) 49.3+5.1kg/m², waist-hip ratio (WHR) 0.96+0.07 and neck circumference (NC) 44.1+4.2 cm. Spirometric values and respiratory pressures were up 80% of predicted values, except for endurance (MVV <80%). Obese with EDS have lower tidal volume. Positive correlation was observed between BMI and EDS, EDS and NC and between snoring and BMI, and negative correlation between EDS and tidal volume (TV), and between snoring and snoring FVC and FEV1. In linear regression the best predictor of pulmonary function was snoring, followed by NC. NC has more obese with higher strength (MEP, p = 0.031) and endurance (MVV p = 0.018) respiratory muscle. Conclusion: Obese with EDS tend to have lower TV. In addition, snoring and NC can better predict pulmonary function in obese when compared with other anthropometric markers or EDS. Obese patients with higher NC tend to have greater capacity for overall strength of respiratory muscles, but may have low muscle endurance
Resumo:
Collembola is one of the most abundant and diverse group of terrestrial arthropods, being at the base of the food chain operating in the decomposition process. They have a wide distribution in the world and can be found in practically all habitats. The knowledge of this distinctive fauna is still deficient in brazilian territory, especially in semi-arid region. The aim of this study was to investigate which climatic variables may act as predictors of species richness, abundance of individuals and compositional structure of the taxocenose of Collembola over 12 months in an area dominated by semi-arid Caatinga vegetation, northeastern Brazil and describe new species of the genus Seira found, more diverse taxon of Collembola in Brazil. Samples were collected in João Câmara, Rio Grande do Norte. Ten plots of 20 x 20 meters were established and the specimens were collected with collection effort of one hour/people using entomological aspirator. The identification and description of the species was carried out by studying the morphology and chaetotaxy. Was performed a multiple regression analysis between species richness and abundance of individuals with climatic variables. A total of 1231 individuals belonging to 15 species, 12 genera and nine families. The greatest richness and abundance of Collembola were found during the rainy season. The genus Seira was the most abundant. Rainfall explained the temporal variation in species richness and abundance of Collembola in the semi-arid region, which is consistent with the biology of these animals. The populations of Collembola showed grouped distribution. Three new species of Seira were described and illustrated and all show similarities with species already registered in the national territory
Resumo:
A introdução dos implantes dentários osseointegrados como uma ferramenta na reabilitação oral de pacientes edêntulos e parcialmente edêntulos é uma realidade no cotidiano do cirurgião-dentista. Estudos reportam uma alta taxa de sucesso da utilização de implantes no tratamento reabilitador. Entretanto, outras investigações têm mostrado a perda desses implantes devido a infecções peri-implantares, como a mucosite e a peri-implantite. O objetivo deste trabalho foi avaliar a frequência das doenças peri-implantares e seus fatores associados em pacientes com implantes dentais em função reabilitados no serviço odontológico da Faculdade de Odontologia da UFRN. Foram examinados 155 indivíduos portadores de 523 implantes e 2718 dentes. Dentes e implantes foram avaliados por meio de sondagem periodontal, observando-se a profundidade de sondagem, retração gengival, bem como foram avaliados índices de placa visível (IPV) e sangramento gengival (ISG) e presença de supuração. Os dados foram armazenados em fichas clínicas e avaliados estatisticamente por meio da estatística descritiva e inferencial. A idade média dos pacientes foi de 54,05 (± 12,61) anos, sendo 79,4% do sexo feminino. As frequências da mucosite, peri-implantite e periodontite em indivíduos foram 54%, 28% e 50%, respectivamente. Dos 523 implantes avaliados, 43% tinham mucosite, 14% peri-implantite e 43% saúde. Os testes Qui-quadrado de Pearson e Exato de Fisher mostraram que as doenças peri-implantares estão associadas as doenças periodontais, uso de medicação, alterações sistêmicas número de implantes, IPV, ISG, ao tempo de função das próteses, região do implante, número de roscas expostas e faixa de mucosa queratinizada (p<0,05). A análise de regressão múltipla, através da regressão binária logística, constatou que indivíduos que faziam uso de medicação (OR = 1,784), com um ISG > 10% (OR = 1,742), com implantes instalados na maxila (OR = 2,654), onde a prótese sobre o implante tinham mais de 2 anos em função (OR = 3,144) e que radiograficamente apresentavam uma perda óssea atingindo a terceira rosca do implante (OR = 4,701) mostram uma associação positiva com as doenças peri-implantares de maneira que esses indivíduos têm mais chances de ter essas doenças. Os resultados sugerem que a frequência das doenças peri-implantares na população em estudo foi de 82% dos pacientes e que estas doenças estão associadas a fatores relacionados aos indivíduos como: a presença da doença periodontal, piores IPV e IS, alterações sistêmicas, uso de medicação e maior número de implantes; e a fatores locais relacionados aos implantes como: ausência ou faixa de mucosa menor que 2mm, implantes na maxila e na região anterior, perda óssea atingindo a terceira rosca do implante e a um tempo de reabilitação prótetica maior que 2 anos
Resumo:
Collembola is one of the most abundant and diverse group of terrestrial arthropods, being at the base of the food chain operating in the decomposition process. They have a wide distribution in the world and can be found in practically all habitats. The knowledge of this distinctive fauna is still deficient in brazilian territory, especially in semi-arid region. The aim of this study was to investigate which climatic variables may act as predictors of species richness, abundance of individuals and compositional structure of the taxocenose of Collembola over 12 months in an area dominated by semi-arid Caatinga vegetation, northeastern Brazil and describe new species of the genus Seira found, more diverse taxon of Collembola in Brazil. Samples were collected in João Câmara, Rio Grande do Norte. Ten plots of 20 x 20 meters were established and the specimens were collected with collection effort of one hour/people using entomological aspirator. The identification and description of the species was carried out by studying the morphology and chaetotaxy. Was performed a multiple regression analysis between species richness and abundance of individuals with climatic variables. A total of 1231 individuals belonging to 15 species, 12 genera and nine families. The greatest richness and abundance of Collembola were found during the rainy season. The genus Seira was the most abundant. Rainfall explained the temporal variation in species richness and abundance of Collembola in the semi-arid region, which is consistent with the biology of these animals. The populations of Collembola showed grouped distribution. Three new species of Seira were described and illustrated and all show similarities with species already registered in the national territory