Jose Lisboa, C. Souza, E. M. Ramos, Silvia dos Santos de Almeida
In the last 50 years, the incidence of dengue grew over 30 times, with the development of the geographical expansion for new countries and currently, reaching small towns and rural areas. It is estimated about over than 50 million of infection by dengue occur annually and approximately 2.5 billion people die in countries where the disease is endemic. In the state of Pará, 4042 cases of dengue were confirmed until October 1st, 2015. At the same period in the year of 2014, 2704 occurrences were registered, which represents an increase of almost 50%. Thus, this work’s objective is to trace the patient’s with dengue profiles in the state of Pará and to verify the relationship between those patients stage of life and the type of dengue with evolution case. For this end, the descriptive analysis technique was utilized, aiming to trace the patient’s profiles confirmed with dengue. The correspondence analysis technique was utilized to verify what was (exclude) the relationship between the patients’s stage of life and the type of dengue fever with evolution case. As the main results, it was noticed that the majority of the patients are female, residing in urban zones and are adults. It was still perceived that elders, children and individuals that had dengue with complications, shock syndrome and hemorrhagic fever had the highest probabilities of dying. Therefore, it is due noticed that is important to give this disease greater attention, above all to the children and elderly stages of life, because, from the results it was evidenced that the individuals on these stages of life are the most prone to die from the disease.
{"title":"DENGUE: WHO IS DYING IN THE STATE OF PARÁ?","authors":"Jose Lisboa, C. Souza, E. M. Ramos, Silvia dos Santos de Almeida","doi":"10.28951/RBB.V36I4.320","DOIUrl":"https://doi.org/10.28951/RBB.V36I4.320","url":null,"abstract":"In the last 50 years, the incidence of dengue grew over 30 times, with the development of the geographical expansion for new countries and currently, reaching small towns and rural areas. It is estimated about over than 50 million of infection by dengue occur annually and approximately 2.5 billion people die in countries where the disease is endemic. In the state of Pará, 4042 cases of dengue were confirmed until October 1st, 2015. At the same period in the year of 2014, 2704 occurrences were registered, which represents an increase of almost 50%. Thus, this work’s objective is to trace the patient’s with dengue profiles in the state of Pará and to verify the relationship between those patients stage of life and the type of dengue with evolution case. For this end, the descriptive analysis technique was utilized, aiming to trace the patient’s profiles confirmed with dengue. The correspondence analysis technique was utilized to verify what was (exclude) the relationship between the patients’s stage of life and the type of dengue fever with evolution case. As the main results, it was noticed that the majority of the patients are female, residing in urban zones and are adults. It was still perceived that elders, children and individuals that had dengue with complications, shock syndrome and hemorrhagic fever had the highest probabilities of dying. Therefore, it is due noticed that is important to give this disease greater attention, above all to the children and elderly stages of life, because, from the results it was evidenced that the individuals on these stages of life are the most prone to die from the disease. ","PeriodicalId":36293,"journal":{"name":"Revista Brasileira de Biometria","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90806539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Latent class analysis (LCA) is used to analyse data about performance of students. The original performance variables in the data set are course grade and approval status. However, those variables were not used directly, instead four new variables were calculated from those previous two, variables which are much more informative about the student performance. Coupled with another variable, say afirmative action, the results give light to an understanding about the performance of the divided by afirmative action, yes or no. Besides of showing the results it is also shown how the changing of the original variables by some suitable transformation of the original ones gives more reliable results. The main result is that armative action students have a lower performance than those coming from private schools. The paper also analyses the subjects grades using latent budget analysis (LBA), and it is found that the variables cited above have a real effect in characterizing the subjects. It is also shown that those results can be used in a process of evaluation on how the subject is being taught.
{"title":"THE PERFORMANCE OF AFFIRMATIVE ACTION STUDENTS AND ANALYSIS OF SUBJECTS GRADES USING LATENT CLASS AND LATENT BUDGET MODELS","authors":"E. Jelihovschi","doi":"10.28951/RBB.V36I4.309","DOIUrl":"https://doi.org/10.28951/RBB.V36I4.309","url":null,"abstract":"Latent class analysis (LCA) is used to analyse data about performance of students. The original performance variables in the data set are course grade and approval status. However, those variables were not used directly, instead four new variables were calculated from those previous two, variables which are much more informative about the student performance. Coupled with another variable, say afirmative action, the results give light to an understanding about the performance of the divided by afirmative action, yes or no. Besides of showing the results it is also shown how the changing of the original variables by some suitable transformation of the original ones gives more reliable results. The main result is that armative action students have a lower performance than those coming from private schools. The paper also analyses the subjects grades using latent budget analysis (LBA), and it is found that the variables cited above have a real effect in characterizing the subjects. It is also shown that those results can be used in a process of evaluation on how the subject is being taught.","PeriodicalId":36293,"journal":{"name":"Revista Brasileira de Biometria","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76107026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A new distribution, the so called beta exponentiated Weibull geometric (BEWG) distribution is proposed. The new distribution is generated from the logit of a beta random variable and includes the exponentiated Weibull geometric distribution as particular case. Various structural properties including explicit expressions for the moments, moment generating function, mean deviation of the new distribution are derived. The estimation of the model parameters is performed by maximum likelihood method. The usefulness of the model was showed by using a real dataset. In order to validate the results a simulation bootstrap is presented in this paper.
{"title":"THE BETA EXPONENTIATED WEIBULL GEOMETRIC DISTRIBUTION: MODELING, STRUCTURAL PROPERTIES, ESTIMATION AND AN APPLICATION TO A CERVICAL INTRAEPITHELIAL NEOPLASIA DATASET","authors":"F. Louzada, I. Elbatal, D. Granzotto","doi":"10.28951/RBB.V36I4.329","DOIUrl":"https://doi.org/10.28951/RBB.V36I4.329","url":null,"abstract":"A new distribution, the so called beta exponentiated Weibull geometric (BEWG) distribution is proposed. The new distribution is generated from the logit of a beta random variable and includes the exponentiated Weibull geometric distribution as particular case. Various structural properties including explicit expressions for the moments, moment generating function, mean deviation of the new distribution are derived. The estimation of the model parameters is performed by maximum likelihood method. The usefulness of the model was showed by using a real dataset. In order to validate the results a simulation bootstrap is presented in this paper.","PeriodicalId":36293,"journal":{"name":"Revista Brasileira de Biometria","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84050395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Survival models with frailty are used when some variables are non-available to explain the occurrence time of an event of interest. This non-availability may be considered as a random effect related to unobserved covariates, or that cannot be measured, such as environmental or genetic factors. This paper focuses on the Gamma-Gompertz (denoted by G-G) model that is one of a class of models that investigate the effects of unobservable heterogeneity. We assume that the baseline mortality rate in the G-G model is the Gompertz model, in which mortality increases exponentially with age and the frailty is a fixed property of the individual, and the distribution of frailty is a gamma distribution. The proposed methodology uses the Laplace transform to find the unconditional survival function in the individual frailty. Estimation is based on maximum likelihood methods and this distribution is compared with its particular case. A simulation study examines the bias, the mean squared errors and the coverage probabilities considering various samples sizes and censored data. A real example with lung cancer data illustrates the applicability of the methodology, where we compared the G-G and without frailty models via criteria which select thebest fitted model to the data.
{"title":"GOMPERTZ REGRESSION MODEL WITH GAMMA FRAILTY: A STUDY ON THE APPLICATION IN LUNG CANCER","authors":"V. Tomazella, E. Milani, Teresa C. M. Dias","doi":"10.28951/RBB.V36I4.312","DOIUrl":"https://doi.org/10.28951/RBB.V36I4.312","url":null,"abstract":"Survival models with frailty are used when some variables are non-available to explain the occurrence time of an event of interest. This non-availability may be considered as a random effect related to unobserved covariates, or that cannot be measured, such as environmental or genetic factors. This paper focuses on the Gamma-Gompertz (denoted by G-G) model that is one of a class of models that investigate the effects of unobservable heterogeneity. We assume that the baseline mortality rate in the G-G model is the Gompertz model, in which mortality increases exponentially with age and the frailty is a fixed property of the individual, and the distribution of frailty is a gamma distribution. The proposed methodology uses the Laplace transform to find the unconditional survival function in the individual frailty. Estimation is based on maximum likelihood methods and this distribution is compared with its particular case. A simulation study examines the bias, the mean squared errors and the coverage probabilities considering various samples sizes and censored data. A real example with lung cancer data illustrates the applicability of the methodology, where we compared the G-G and without frailty models via criteria which select thebest fitted model to the data. ","PeriodicalId":36293,"journal":{"name":"Revista Brasileira de Biometria","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80385612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. F. Ferreira, L. Chaves, Devanil Jaques de Souza
The present paper intends to revisit the distribution of the ratio of the range to the sample standard deviation, known as the distribution of the internally studentized range, in the normal case. This distribution has its importance recognized in several areas, as quality control and inference, for testing the lack of homogeneity of the data or kurtosis. An alternative distribution to the one presented by David et al. (1954), based on the distribution of the maximum, is proposed. We exhibit a detailed proof for the distribution of the internally studentized range in the normal case and sample size 3. We also provide a new result: the distribution for the uniform case with sample of size 3.
本文打算重新审视在正常情况下，范围与样本标准差之比的分布，即内部研究范围的分布。这种分布的重要性在几个领域得到了认可，如质量控制和推理，用于测试数据的缺乏同质性或峰度。David et al.(1954)提出了一种基于最大值分布的替代分布。我们展示了在正常情况和样本容量3下内部研究范围分布的详细证明。我们还提供了一个新的结果:样本大小为3的均匀情况下的分布。
{"title":"THE THEORY OF THE INTERNALLY STUDENTIZED RANGE DISTRIBUTION REVISITED","authors":"D. F. Ferreira, L. Chaves, Devanil Jaques de Souza","doi":"10.28951/RBB.V36I4.308","DOIUrl":"https://doi.org/10.28951/RBB.V36I4.308","url":null,"abstract":"The present paper intends to revisit the distribution of the ratio of the range to the sample standard deviation, known as the distribution of the internally studentized range, in the normal case. This distribution has its importance recognized in several areas, as quality control and inference, for testing the lack of homogeneity of the data or kurtosis. An alternative distribution to the one presented by David et al. (1954), based on the distribution of the maximum, is proposed. We exhibit a detailed proof for the distribution of the internally studentized range in the normal case and sample size 3. We also provide a new result: the distribution for the uniform case with sample of size 3.","PeriodicalId":36293,"journal":{"name":"Revista Brasileira de Biometria","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84308339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
O. C. N. Pereira, P. V. C. Pereira, Altair Bertonha, I. Previdelli
The purpose of this work was to evaluate the accumulated evapotranspiration of stevia, planted in 40 pots, over a period of 27 days according to four irrigation levels through a nonlinear mixed eects model and, with this model, to verify if we can maximize the stevia's evapotranspiration with a lower than usual water level. When the humidity of the substrate reached 50% of its maximum capacity retention, we added water to raise the humidity according to the four treatments: W1 = 62:5%; W2 = 75:0%; W3 = 87:5%; W4 = 100:0%. Although the crop production depends on the availability of water in the soil, there is a limit for the total yield. The water levels, W3 and W4, resulted in similar total accumulated evapotranspiration, while all the last three water levels, W2, W3 and W4 had close shoot dry matter masses at the end of the experiment. We showed that is possible to nd an optimal level of crop production with a rational use of the available water resources.
{"title":"LONGITUDINAL DATA ANALYSIS OF STEVIA REBAUDIANA EVAPOTRANSPIRATION ACCORDING TO WATER LEVELS","authors":"O. C. N. Pereira, P. V. C. Pereira, Altair Bertonha, I. Previdelli","doi":"10.28951/RBB.V36I4.306","DOIUrl":"https://doi.org/10.28951/RBB.V36I4.306","url":null,"abstract":"The purpose of this work was to evaluate the accumulated evapotranspiration of stevia, planted in 40 pots, over a period of 27 days according to four irrigation levels through a nonlinear mixed eects model and, with this model, to verify if we can maximize the stevia's evapotranspiration with a lower than usual water level. When the humidity of the substrate reached 50% of its maximum capacity retention, we added water to raise the humidity according to the four treatments: W1 = 62:5%; W2 = 75:0%; W3 = 87:5%; W4 = 100:0%. Although the crop production depends on the availability of water in the soil, there is a limit for the total yield. The water levels, W3 and W4, resulted in similar total accumulated evapotranspiration, while all the last three water levels, W2, W3 and W4 had close shoot dry matter masses at the end of the experiment. We showed that is possible to nd an optimal level of crop production with a rational use of the available water resources. ","PeriodicalId":36293,"journal":{"name":"Revista Brasileira de Biometria","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79084634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
O. G. M. Guera, José Antônio Aleixo da Silva, R. Ferreira, H. B. Medel, D. Lazo
The present study was carried out to compare the performances of regression models and Artificial Neural Networks (ANNs) in hypsometric relationships modeling and to analyze the influence of ANN type and sample size on ANN performance. The database was consisted by 65 circular plots of 500 m² in which Diameter at Breast Height - DBH (cm) and Total Height - Ht (m) of 2538 trees were measured in plantations of Pinus caribaea var. caribaea in Macurije forest company, Cuba. The study was carried out in three stages: i) Fit of traditional hypsometric models and sigmoidal growth models; ii) ANNs training and comparison of the selected ANN with the regression model selected; iii) Analysis of sample size and ANN type influences on the estimates precision by means of a completely random experimental design with 5x2 factorial arrangement, with the factors sample size (N) and ANN type (R). The results indicated that the best equation to estimate trees heights was that of Gompertz. The ANNs MLP 1-4-1 and MLP 8-4-1 were superior to the selected equation (Gompertz). Multi-Layer Perceptron ANNs generated more accurate estimates and their performances were less influenced by the sample size.
{"title":"ARTIFICIAL NEURAL NETWORKS FOR MODELING HYPSOMETRIC RELATIONSHIPS OF Pinus caribaea Morelet var. caribaea Barr. & Golf.","authors":"O. G. M. Guera, José Antônio Aleixo da Silva, R. Ferreira, H. B. Medel, D. Lazo","doi":"10.28951/RBB.V36I4.315","DOIUrl":"https://doi.org/10.28951/RBB.V36I4.315","url":null,"abstract":"The present study was carried out to compare the performances of regression models and Artificial Neural Networks (ANNs) in hypsometric relationships modeling and to analyze the influence of ANN type and sample size on ANN performance. The database was consisted by 65 circular plots of 500 m² in which Diameter at Breast Height - DBH (cm) and Total Height - Ht (m) of 2538 trees were measured in plantations of Pinus caribaea var. caribaea in Macurije forest company, Cuba. The study was carried out in three stages: i) Fit of traditional hypsometric models and sigmoidal growth models; ii) ANNs training and comparison of the selected ANN with the regression model selected; iii) Analysis of sample size and ANN type influences on the estimates precision by means of a completely random experimental design with 5x2 factorial arrangement, with the factors sample size (N) and ANN type (R). The results indicated that the best equation to estimate trees heights was that of Gompertz. The ANNs MLP 1-4-1 and MLP 8-4-1 were superior to the selected equation (Gompertz). Multi-Layer Perceptron ANNs generated more accurate estimates and their performances were less influenced by the sample size.","PeriodicalId":36293,"journal":{"name":"Revista Brasileira de Biometria","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86852066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Carvalho, M. Mischan, J. R. S. Passos, S. Z. D. Pinho
The purpose of this study was to establish contrasts in multivariate nonlinear mixed models to verify the effects of treatments in experiments with longitudinal data and multiple responses. The evaluated nonlinear functions were the three parameters curves logistic, Gompertz and von Bertalanffy. The random variables were added to the fixed parameters, asymptote α , abscissa of the inflection point β, and parameter γ. The best fitted model was expanded with covariates, which establish orthogonal contrasts, in order to verify main effects and interactions in factorial experiments. The methodology was applied to analyse data of an experiment with citrus, in which case the logistic bivariate mixed effects model was the best fit. The chosen model allowed comparisons between treatments in a global context of more than one dependent variable and throughout the measurement period.
{"title":"THE USE OF CONTRASTS IN MULTIVARIATE NONLINEAR MIXED MODELS TO COMPARE TREATMENTS IN LONGITUDINAL FACTORIAL EXPERIMENTS","authors":"L. Carvalho, M. Mischan, J. R. S. Passos, S. Z. D. Pinho","doi":"10.28951/RBB.V36I4.314","DOIUrl":"https://doi.org/10.28951/RBB.V36I4.314","url":null,"abstract":"The purpose of this study was to establish contrasts in multivariate nonlinear mixed models to verify the effects of treatments in experiments with longitudinal data and multiple responses. The evaluated nonlinear functions were the three parameters curves logistic, Gompertz and von Bertalanffy. The random variables were added to the fixed parameters, asymptote α , abscissa of the inflection point β, and parameter γ. The best fitted model was expanded with covariates, which establish orthogonal contrasts, in order to verify main effects and interactions in factorial experiments. The methodology was applied to analyse data of an experiment with citrus, in which case the logistic bivariate mixed effects model was the best fit. The chosen model allowed comparisons between treatments in a global context of more than one dependent variable and throughout the measurement period. ","PeriodicalId":36293,"journal":{"name":"Revista Brasileira de Biometria","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87461878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
RESUMO: O método Peaks Over Threshold (POT) consiste no ajuste da distribuição generalizada de Pareto aos excessos aleatórios independentes e identicamente distribuídos acima de um limiar elevado. Neste estudo, usamos a metodologia POT para estimar os parâmetros da distribuição dos excessos na aplicação ao salto em comprimento do atletismo, no período de 1935 a 2016 nos homens e de 1964 a 2016 nas mulheres. Determinado o limiar u, adequado, são apresentadas as estimativas de alguns parâmetros de interesse, como a probabilidade de excedência, os quantis extremais, o limite superior do suporte e os níveis e períodos de retorno. Nos homens, os resultados apontam para u=8,45m com 0 ˆ e nas mulheres u = 7,06m com 0 ˆ . Prevê-se que o recorde mundial seja batido, em média, acima de 585 recordes individuais nos homens, e acima de 427 recordes individuais nas mulheres.
{"title":"Aplicação da metodologia Peaks Over Threshold ao Salto em Comprimento do Atletismo","authors":"D. Silva, F. Caeiro, M. M. Oliveira","doi":"10.28951/RBB.V36I4","DOIUrl":"https://doi.org/10.28951/RBB.V36I4","url":null,"abstract":" RESUMO: O método Peaks Over Threshold (POT) consiste no ajuste da distribuição generalizada de Pareto aos excessos aleatórios independentes e identicamente distribuídos acima de um limiar elevado. Neste estudo, usamos a metodologia POT para estimar os parâmetros da distribuição dos excessos na aplicação ao salto em comprimento do atletismo, no período de 1935 a 2016 nos homens e de 1964 a 2016 nas mulheres. Determinado o limiar u, adequado, são apresentadas as estimativas de alguns parâmetros de interesse, como a probabilidade de excedência, os quantis extremais, o limite superior do suporte e os níveis e períodos de retorno. Nos homens, os resultados apontam para u=8,45m com 0 ˆ e nas mulheres u = 7,06m com 0 ˆ . Prevê-se que o recorde mundial seja batido, em média, acima de 585 recordes individuais nos homens, e acima de 427 recordes individuais nas mulheres.","PeriodicalId":36293,"journal":{"name":"Revista Brasileira de Biometria","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88348524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The aim of the study was evaluate and compare the efficiency of Bayesian and frequentist approach to describe the rumen degradation of NDF. Simulated data was composed by four scenarios: regular restriction in the number of incubation times, random loss of incubation times, loss of specific parts of degradation curves, variation in the precision of the incubations procedures. Two real datasets was used, these real data encompassed the evaluation of NDF degradation of a tropical grass (Brachiaria decumbes). The model was fitted according their characteristics approach and compared by plots and assessors. The Bayesian and frequentist approach presented reliable estimates of degradation parameters for the majority of the data tested. Therefore, in specific cases with short random records number, the Bayesian approach showed greater bias of the estimates of incubation residue and estimates of degradation rate without a biological coherence of the parameters, compared to frequentist inference. In another words, the Bayesian approach fitted with prior diffuse, presented less flexible. Nevertheless, it is emphasized the importance of the background information before the modeling, mainly for the Bayesian approach, in order to define proper prior distributions. Future thorough studies about the influence of non-informative prior for the parameters are necessary.
{"title":"BAYESIAN AND FREQUENTIST APPROACHES FOR FITTING THE GAMMA-TIME-DEPENDENT MODEL TO DESCRIBE NEUTRAL DETERGENT FIBER DEGRADATION","authors":"H. Bonfá, E. Detmann, F. F. Silva, J. Figueiras","doi":"10.28951/RBB.V36I3.260","DOIUrl":"https://doi.org/10.28951/RBB.V36I3.260","url":null,"abstract":"The aim of the study was evaluate and compare the efficiency of Bayesian and frequentist approach to describe the rumen degradation of NDF. Simulated data was composed by four scenarios: regular restriction in the number of incubation times, random loss of incubation times, loss of specific parts of degradation curves, variation in the precision of the incubations procedures. Two real datasets was used, these real data encompassed the evaluation of NDF degradation of a tropical grass (Brachiaria decumbes). The model was fitted according their characteristics approach and compared by plots and assessors. The Bayesian and frequentist approach presented reliable estimates of degradation parameters for the majority of the data tested. Therefore, in specific cases with short random records number, the Bayesian approach showed greater bias of the estimates of incubation residue and estimates of degradation rate without a biological coherence of the parameters, compared to frequentist inference. In another words, the Bayesian approach fitted with prior diffuse, presented less flexible. Nevertheless, it is emphasized the importance of the background information before the modeling, mainly for the Bayesian approach, in order to define proper prior distributions. Future thorough studies about the influence of non-informative prior for the parameters are necessary.","PeriodicalId":36293,"journal":{"name":"Revista Brasileira de Biometria","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85759921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：