Departamento de estadisticas y ciencia de datos
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Ítem A bimodal discrete shifted poisson distribution. A case study of tourists' length of stay(2020) Gómez-Déniz, E.; Pérez-Rodríguez, J.V.; Reyes, J.; Gómez, H.W.Ítem A Bivariate Power Lindley Survival Distribution(2024) Guillermo Martínez Flórez; Barry C. Arnold; Héctor W. GómezWe introduce and investigate the properties of new families of univariate and bivariate distributions based on the survival function of the Lindley distribution. The univariate distribution,to reflect the nature of its construction, is called a power Lindley survival distribution. The basic distributional properties of this model are described. Maximum likelihood estimates of the parameters of the distribution are studied and the corresponding information matrix is identified. A bivariate power Lindley survival distribution is introduced using the technique of conditional specification.The corresponding joint density and marginal and conditional densities are derived. The product moments of the distribution are obtained, together with bounds on the range of correlations that can be exhibited by the model. Estimation of the parameters of the model is implemented by maximizing the corresponding pseudo-likelihood function. The asymptotic variance–covariance matrix of these estimates is investigated. A simulation study is performed to illustrate the performance of these parameter estimates. Finally some examples of model fitting using real-world data sets are describedÍtem A Gamma-type distribution with applications(2020) Iriarte, Y.A.; Varela, H.; Gómez, H.J.; Gómez, H.W.Ítem A Modified Cure Rate Model Based on a Piecewise Distribution with Application to Lobular Carcinoma Data(2024) Yolanda M. Gómez; John L. Santibañez; Vinicius F. Calsavara; Héctor W. Gómez; Diego I. GallardoA novel cure rate model is introduced by considering, for the number of concurrent causes, the modified power series distribution and, for the time to event, the recently proposed power piecewise exponential distribution. This model includes a wide variety of cure rate models, such as binomial, Poisson, negative binomial, Haight, Borel, logarithmic, and restricted generalized Poisson. Some characteristics of the model are examined, and the estimation of parameters is performed using the Expectation–Maximization algorithm. A simulation study is presented to evaluate the performance of the estimators in finite samples. Finally, an application in a real medical dataset from a population-based study of incident cases of lobular carcinoma diagnosed in the state of São Paulo, Brazil, illustrates the advantages of the proposed model compared to other common cure rate models in the literature, particularly regarding the underestimation of the cure rate in other proposals and the improved precision in estimating the cure rate of our proposal.Ítem A New Generalization of the Truncated Gumbel Distributionwith Quantile Regression and Applications(2024) Héctor J. Gómez; Karol I. Santoro; Diego Ayma; Isaac E. Cortés; Isaac E. Cortés; Tiago M. MagalhãesIn this article, we introduce a new model with positive support. This model is an extension of the truncated Gumbel distribution, where a shape parameter is incorporated that provides greater flexibility to the new model. The model is parameterized in terms of the p-thquantile of the distribution to perform quantile regression in this model. An extensive simulation study demonstrates the good performance of the maximum likelihood estimators in finite samples. Finally, two applications to real datasets related to the level of beta-carotene and body mass index are presented.Ítem A parametric quantile regression model for asymmetric response variables on the real line(2020) Gallardo, D.I.; Bourguignon, M.; Galarza, C.E.; Gómez, H.W.Ítem A power maxwell distribution with heavy tails and applications(2020) Segovia, F.A.; Gómez, Y.M.; Venegas, O.; Gómez, H.W.Ítem A reliability model based on the incomplete generalized integro-exponential function(2020) Astorga, J.M.; Reyes, J.; Santoro, K.I.; Venegas, O.; Gómez, H.W.Ítem A transmuted version of the generalized half-normal distribution(2019) Salinas, H.S.; Iriarte, Y.A.; Astorga, J.M.Ítem A Weighted Skew-Logistic Distribution with Applicationsto Environmental Data(2024) Isaac Cortés; Jimmy Reyes; Yuri A. IriarteSkewness and bimodality properties are frequently observed when analyzing environmental data such as wind speeds, precipitation levels, and ambient temperatures. As an alternative to modeling data exhibiting these properties, we propose a flexible extension of the skew-logistic distribution. The proposal corresponds to a weighted version of the skewed logistic distribution, defined by a parametric weight function that allows shapes with up to three modes for the resulting density.Parameter estimation via the maximum likelihood approach is discussed. Simulation experiments are carried out to evaluate the performance of the estimators. Applications to environmental data illustrating the utility of the proposal are presented.Ítem An asymmetric bimodal distribution with application to quantile regression(2019) Gómez, Y.M.; Gómez-Déniz, E.; Venegas, O.; Gallardo, D.I.; Gómez, H.W.Ítem An asymmetric distribution with heavy tails and its expectation-maximization (EM) algorithm implementation(2019) Olmos, N.M.; Venegas, O.; Gómez, Y.M.; Iriarte, Y.A.Ítem An Extension of the Akash Distribution: Properties, Inference and Application(2024) Yolanda M. Gómez; Luis Firinguetti Limone; Diego I. Gallardo; Héctor W. GómezIn this article we introduce an extension of the Akash distribution. We use the slash methodology to make the kurtosis of the Akash distribution more flexible. We study the general probability density function of this new model, some properties, moments, skewness and kurtosis coefficients. Statistical inference is performed using the methods of moments and maximum likelihood via the EM algorithm. A simulation study is carried out to observe the behavior of the maximum likelihood estimator. An application to a real data set with high kurtosis is considered, where it is shown that the new distribution fits better than other extensions of the Akash distribution.Ítem An Extension of the Fréchet Distribution and Applications(2024) Yolanda M. Gómez; Inmaculada Barranco Chamorro; Jaime S. Castillo; Héctor W. GómezThis paper presents the Slash-Exponential-Fréchet distribution, which is an expanded version of the Fréchet distribution. Through its stochastic representation, probability distribution function, moments and other relevant features are obtained. Evidence supports that the updated model displays a lighter right tail than the Fréchet model and is more flexible as for skewness and kurtosis. Results on maximum likelihood estimators are given. Our proposition’s applicability is demonstrated through a simulation study and the evaluation of two real-world datasets.Ítem Betel and tobacco chewing habit and its relation to risk factors for periodontal disease(2018) Giovannoni, M.L.; Valdivia-Gandur, I.; Lozano de Luaces, V.; Varela Véliz, H.; Balasubbaiah, Y.; Chimenos-Küstner, E.Ítem Bimodal extension based on the skew-t-normal distribution(2019) Amiri, M.; Gómez, H.W.; Jamalizadeh, A.; Towhidi, M.Ítem Bivariate power-skew-elliptical distribution(2020) Martínez-Flórez, G.; Tovar-Falón, R.; Gómez, H.W.Ítem Censored bimodal symmetric-asymmetric families(2018) Martínez-Flórez, G.; Bolfarine, H.; Gómez, H.W.Ítem Corrigendum to: Skew-normal alpha-power model (Statistics, (2014), 48, 6, (1414-1428), 10.1080/02331888.2013.826659)(2018) Salinas, H.S.; Gómez, H.W.; Martínez-Flórez, G.; Bolfarine, H.Ítem Extended exponential regression model: Diagnostics and application to mineral data(2020) Gómez, Y.M.; Gallardo, D.I.; Leão, J.; Gómez, H.W.
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