Hamid Bidram - Academia.edu (original) (raw)

Papers by Hamid Bidram

Research paper thumbnail of Relationships between reduction of income, health and job satisfaction before retirement with psychological well-being after that it according to moderating role of job planning, bridge job and retirement earlier and later than expected

Knowledge & Research in Applied Psychology, Dec 22, 2019

Research paper thumbnail of A note on exponentiated geometric distribution: Another generalization of geometric distribution

Communications in Statistics, May 26, 2015

Research paper thumbnail of Structural Model of the Impact of Organizational Intelligence and Quantum Management Skills on Organizational Agility Capabilities (A Study in Higher Education)

Higher Education Letter, Jan 20, 2021

Research paper thumbnail of Applications of resampling methods in multivariate Liu estimator

Computational Statistics, Dec 30, 2022

Research paper thumbnail of Goodness-of-Fit Tests Based on Correcting Moments of Entropy Estimators

Communications in Statistics - Simulation and Computation, 2013

This article may be used for research, teaching, and private study purposes. Any substantial or s... more This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae, and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand, or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.

Research paper thumbnail of Discrete generalized exponential distribution of a second type

Statistics, 2013

ABSTRACT In this paper, we shall attempt to introduce another discrete analogue of the generalize... more ABSTRACT In this paper, we shall attempt to introduce another discrete analogue of the generalized exponential distribution of Gupta and Kundu [Generalized exponential distributions, Aust. N. Z. J. Stat. 41(2) (1999), pp. 173–188], different to that of Nekoukhou et al. [A discrete analogue of the generalized exponential distribution, Comm. Stat. Theory Methods,DOI: 10.1080/03610926.2011.555044]. This new discrete distribution, which we shall call a discrete generalized exponential distribution of the second type (DGE2(α, p)), can be viewed as another generalization of the geometric distribution. We shall first study some basic distributional and moment properties, as well as order statistics distributions of this family of new distributions. Certain compounded DGE2(α, p) distributions are also discussed as the results of which some previous lifetime distributions such as that of Adamidis and Loukas [A lifetime distribution with decreasing failure rate, Statist. Probab. Lett. 39 (1998), pp. 35–42] follow as corollaries. Then, we will investigate estimation of the parameters involved. Finally, we will examine the model with a real data set.

Research paper thumbnail of Time indexed covariate analysis of the administered vaccine doses on Covid-19 spread

In this study, we focus on the spread of COVID–19 on besides of vaccination of this disease. Tota... more In this study, we focus on the spread of COVID–19 on besides of vaccination of this disease. Total infected cases of COVID–19 have considered and model it by a light/heavy tailed auto–regressive model with innovations belong on the flexible class of the two-piece scale mixtures of normal (TP–SMN) family. Also considering the covariate variables which are indexed by time are considered in the model to more accuracy of modeling. An EM type algorithm has considered for finding the maximum likelihood estimations of the model parameters. Modelling and prediction of infected numbers of COVID–19 in the U.S. has considered and vaccinated numbers of COVID–19 is considered as auxiliary (covariate) in the model.

Research paper thumbnail of Univariate and bivariate extensions of the generalized exponential distributions

Mathematica Slovaca, 2021

The main aim of this paper is to introduce a new class of continuous generalized exponential dist... more The main aim of this paper is to introduce a new class of continuous generalized exponential distributions, both for the univariate and bivariate cases. This new class of distributions contains some newly developed distributions as special cases, such as the univariate and also bivariate geometric generalized exponential distribution and the exponential-discrete generalized exponential distribution. Several properties of the proposed univariate and bivariate distributions, and their physical interpretations, are investigated. The univariate distribution has four parameters, whereas the bivariate distribution has five parameters. We propose to use an EM algorithm to estimate the unknown parameters. According to extensive simulation studies, we see that the effectiveness of the proposed algorithm, and the performance is quite satisfactory. A bivariate data set is analyzed and it is observed that the proposed models and the EM algorithm work quite well in practice.

Research paper thumbnail of Skewed Auto-Regressive Process with Exogenous Input Variables: An Application in the Administered Vaccine Doses on Covid-19 Spread

Fractals, 2022

This study focuses on the prevalence of COVID-19 disease along with vaccination in the United Sta... more This study focuses on the prevalence of COVID-19 disease along with vaccination in the United States. We have considered the daily total infected cases of COVID-19 with total vaccinated cases as exogenous input and modeled them using light/heavy tailed auto-regressive with exogenous input model based on the innovations that belong to the flexible class of the twopiece scale mixtures of normal (TP-SMN) family. We have shown that the prediction of COVID-19 spread is affected by the rate of vaccine injection. In fact, the presence of exogenous input variables in time series models not only increases the accuracy of modeling, but also causes better and closer approximations in some issues including predictions. An Expectation-Maximization (EM) type algorithm has been considered for finding the maximum likelihood (ML) estimations of the model parameters, and modelling as well as predicting the infected numbers of COVID-19 in the presence of the vaccinated cases in the U.S.

Research paper thumbnail of Robust clustering of COVID-19 cases across U.S. counties using mixtures of asymmetric time series models with time varying and freely indexed covariates

Journal of Applied Statistics, 2022

In this paper, we develop a mixture of autoregressive (MoAR) process model with time varying and ... more In this paper, we develop a mixture of autoregressive (MoAR) process model with time varying and freely indexed covariates under the flexible class of two–piece distributions using the scale mixtures of normal (TP-SMN) family. This novel family of time series (TP-SMN-MoAR) models was used to examine flexible and robust clustering of reported cases of Covid-19 across 313 counties in the U.S. The TP-SMN distributions allow for symmetrical/ asymmetrical distributions as well as heavy-tailed distributions providing for flexibility to handle outliers and complex data. Developing a suitable hierarchical representation of the TP-SMN family enabled the construction of a pseudo-likelihood function to derive the maximum pseudo-likelihood estimates via an EM-type algorithm.

Research paper thumbnail of رابطة کاهش درآمد، سلامت و خشنودی شغلی قبل از بازنشستگی با بهزیستی روانشناختی پس از آن با توجه به نقش تعدیلی وجود برنامه بازنشستگی، شغل در دوره گذار و انتظار بازنشستگی زودتر و دیرتر از انتظار

هدف این پژوهش، بررسی نقش تعدیلی سه متغیر برنامة بازنشستگی، مرحلة بازنشستگی و زمان بازنشستگی در را... more هدف این پژوهش، بررسی نقش تعدیلی سه متغیر برنامة بازنشستگی، مرحلة بازنشستگی و زمان بازنشستگی در رابطة بین کاهش درآمد، سلامت و خشنودی قبل از بازنشستگی با بهزیستی روان‌شناختی پس از آن است. روش پژوهش توصیفی رابطه‌ای است. جامعة آماری پژوهش، تمام کارکنان در معرض بازنشستگی در مجموعه‌ای از سازمان‌های صنعتی شهر اصفهان بوده است. برای سنجش فرضیات نمونه‌ای 893 نفری به روش در دسترس از کارکنان سازمان‌های اصفهان انتخاب شدند و به ابزارهای پژوهش شامل مقیاس CES-D (رادلف، 1977) و سؤالات مربوط به کاهش درآمد، سلامت، خشنودی شغلی قبل از بازنشستگی، همگی از پیمایش بازنشستگی و سلامت (HRS, 1992)، برنامه بازنشستگی و انتظار بازنشستگی وگلسنانگ (2014) پاسخ دادند. برای تحلیل داده‌ها از ضریب همبستگی و تحلیل زیرگروه‌ها برای تحلیل تعدیلی استفاده شد. نتایج نشان داد که رابطة بین خشنودی شغلی و بهزیستی قبل از بازنشستگی با بهزیستی روان‌شناختی بعد از بازنشستگی مثبت و رابطة بین فاصلة مورد انتظار تا بازنشستگی، گزارش فرد از کاهش سلامت و گزارش پزشکی کاهش سلامت با بهزیستی روان‌شناختی پس از بازنشستگی منفی است (01/0>P).

Research paper thumbnail of Archetypal Associations of Geometric Shapes: Lessons for Marketing Managers

‫مدیریت بازرگانی, 2018

The study seeks to identify how Iranian consumers (Isfahan as the case study) perceive archetypes... more The study seeks to identify how Iranian consumers (Isfahan as the case study) perceive archetypes. Drawing on the Theory of Shape Symbolism, the study also addresses geometric shapes as potential elements in conveying archetypal meaning to the brands. Findings from several preliminary studies and seventy-seven semi-structured in-depth interviews in the main study revealed that, in spite of some similarities, Isfahan citizens are somewhat different in their perception of archetypes compared to western consumers. Moreover, the most and the least fitting shape(s) with each archetype were identified. Respondents' archetypal associations with shapes are based on both intrinsic meaning stemming from shape's attributes such as symmetry, angularity and number of sides, and referential meaning of shapes. In contrast to the existing literature on geometric shapes, angularity is not the only shape characteristic to affect archetypal associations and is not proved influential in all arc...

Research paper thumbnail of On the Liu estimator in the beta and Kumaraswamy regression models: A comparative study

Communications in Statistics - Theory and Methods, 2021

Research paper thumbnail of The relation between quantum management skills and organizational agility capabilities with the mediating role of organizational intelligence

Research paper thumbnail of The Phenomenology of the Experience of Experts and Novice Managers in the Oil Industry to Identify Their Cognitive Differences

Research paper thumbnail of Double bounded Kumaraswamy-power series class of distributions

In this paper, we will introduce the new Kumaraswamy-power series class of distributions. This ne... more In this paper, we will introduce the new Kumaraswamy-power series class of distributions. This new class is obtained by compounding the Kumaraswamy distribution of Kumaraswamy (1980) and the family of power series distributions. The new class contains some new double bounded distributions such as the Kumaraswamy-geometric, -Poisson, -logarithmic and -binomial, which are used widely in hydrology and related areas. In addition, the corresponding hazard rate function of the new class can be increasing, decreasing, bathtub and upside-down bathtub. Some basic properties of this class of distributions such as the moment generating function, moments and order statistics are studied. Some special members of the class are also investigated in detail. The maximum likelihood method is used for estimating the unknown parameters of the members of the new class. Finally, an application of the proposed class is illustrated using a real data set.

Research paper thumbnail of The beta Weibull-geometric distribution

Journal of Statistical Computation and Simulation, 2013

ABSTRACT A new five-parameter distribution called the beta Weibull-geometric (BWG) distribution i... more ABSTRACT A new five-parameter distribution called the beta Weibull-geometric (BWG) distribution is proposed. The new distribution is generated from the logit of a beta random variable and includes the Weibull-geometric distribution of Barreto-Souza et al. [TheWeibull-geometric distribution, J. Stat. Comput. Simul. 81 (2011), pp. 645–657], beta Weibull (BW), beta exponential, exponentiated Weibull, and some other lifetime distributions as special cases. A comprehensive mathematical treatment of this distribution is provided. The density function can be expressed as an infinite mixture of BW densities and then we derive some mathematical properties of the new distribution from the corresponding properties of the BW distribution. The density function of the order statistics and also estimation of the stress–strength parameter are obtained using two general expressions. To estimate the model parameters, we use the maximum likelihood method and the asymptotic distribution of the estimators is also discussed. The capacity of the new distribution are examined by various tools, using two real data sets.

Research paper thumbnail of Double bounded Kumaraswamy-power series class of distributions

In this paper, we will introduce the new Kumaraswamy-power series class of distributions. This ne... more In this paper, we will introduce the new Kumaraswamy-power series class of distributions. This new class is obtained by compounding the Kumaraswamy distribution of Kumaraswamy (1980) and the family of power series distributions. The new class contains some new double bounded distributions such as the Kumaraswamy-geometric,-Poisson,-logarithmic and-binomial, which are used widely in hydrology and related areas. In addition, the corresponding hazard rate function of the new class can be increasing, decreasing, bathtub and upside-down bathtub. Some basic properties of this class of distributions such as the moment generating function, moments and order statistics are studied. Some special members of the class are also investigated in detail. The maximum likelihood method is used for estimating the unknown parameters of the members of the new class. Finally, an application of the proposed class is illustrated using a real data set. MSC: 60E05, 62E10.

Research paper thumbnail of The beta-Weibull geometric distribution

Statistics, 2011

We propose a new distribution, the so-called beta-Weibull geometric distribution, whose failure r... more We propose a new distribution, the so-called beta-Weibull geometric distribution, whose failure rate function can be decreasing, increasing or an upside-down bathtub. This distribution contains special sub-models the exponential geometric [K. Adamidis and S. Loukas, A lifetime distribution with decreasing failure rate, Statist. Probab. Lett. 39 (1998), pp. 35–42], beta exponential [S. Nadarajah and S. Kotz, The exponentiated type distributions, Acta Appl. Math. 92 (2006), pp. 97–111; The beta exponential distribution, Reliab. Eng. Syst. Saf. 91 (2006), pp. 689–697], Weibull geometric [W. Barreto-Souza, A.L. de Morais, and G.M. Cordeiro, The Weibull-geometric distribution, J. Stat. Comput. Simul. 81 (2011), pp. 645–657], generalized exponential geometric [R.B. Silva, W. Barreto-Souza, and G.M. Cordeiro, A new distribution with decreasing, increasing and upside-down bathtub failure rate, Comput. Statist. Data Anal. 54 (2010), pp. 935–944; G.O. Silva, E.M.M. Ortega, and G.M. Cordeiro, ...

Research paper thumbnail of The exponentiated discrete Weibull distribution

In this paper, the exponentiated discrete Weibull distribution is introduced. This new generaliza... more In this paper, the exponentiated discrete Weibull distribution is introduced. This new generalization of the discrete Weibull distribution can also be considered as a discrete analog of the exponentiated Weibull distribution. A special case of this exponentiated discrete Weibull distribution defines a new generalization of the discrete Rayleigh distribution for the first time in the literature. In addition, discrete generalized exponential and geometric distributions are some special sub-models of the new distribution. Here, some basic distributional properties, moments, and order statistics of this new discrete distribution are studied. We will see that the hazard rate function can be increasing, decreasing, bathtub, and upside-down bathtub shaped. Estimation of the parameters is illustrated using the maximum likelihood method. The model with a real data set is also examined.

Research paper thumbnail of Relationships between reduction of income, health and job satisfaction before retirement with psychological well-being after that it according to moderating role of job planning, bridge job and retirement earlier and later than expected

Knowledge & Research in Applied Psychology, Dec 22, 2019

Research paper thumbnail of A note on exponentiated geometric distribution: Another generalization of geometric distribution

Communications in Statistics, May 26, 2015

Research paper thumbnail of Structural Model of the Impact of Organizational Intelligence and Quantum Management Skills on Organizational Agility Capabilities (A Study in Higher Education)

Higher Education Letter, Jan 20, 2021

Research paper thumbnail of Applications of resampling methods in multivariate Liu estimator

Computational Statistics, Dec 30, 2022

Research paper thumbnail of Goodness-of-Fit Tests Based on Correcting Moments of Entropy Estimators

Communications in Statistics - Simulation and Computation, 2013

This article may be used for research, teaching, and private study purposes. Any substantial or s... more This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae, and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand, or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.

Research paper thumbnail of Discrete generalized exponential distribution of a second type

Statistics, 2013

ABSTRACT In this paper, we shall attempt to introduce another discrete analogue of the generalize... more ABSTRACT In this paper, we shall attempt to introduce another discrete analogue of the generalized exponential distribution of Gupta and Kundu [Generalized exponential distributions, Aust. N. Z. J. Stat. 41(2) (1999), pp. 173–188], different to that of Nekoukhou et al. [A discrete analogue of the generalized exponential distribution, Comm. Stat. Theory Methods,DOI: 10.1080/03610926.2011.555044]. This new discrete distribution, which we shall call a discrete generalized exponential distribution of the second type (DGE2(α, p)), can be viewed as another generalization of the geometric distribution. We shall first study some basic distributional and moment properties, as well as order statistics distributions of this family of new distributions. Certain compounded DGE2(α, p) distributions are also discussed as the results of which some previous lifetime distributions such as that of Adamidis and Loukas [A lifetime distribution with decreasing failure rate, Statist. Probab. Lett. 39 (1998), pp. 35–42] follow as corollaries. Then, we will investigate estimation of the parameters involved. Finally, we will examine the model with a real data set.

Research paper thumbnail of Time indexed covariate analysis of the administered vaccine doses on Covid-19 spread

In this study, we focus on the spread of COVID–19 on besides of vaccination of this disease. Tota... more In this study, we focus on the spread of COVID–19 on besides of vaccination of this disease. Total infected cases of COVID–19 have considered and model it by a light/heavy tailed auto–regressive model with innovations belong on the flexible class of the two-piece scale mixtures of normal (TP–SMN) family. Also considering the covariate variables which are indexed by time are considered in the model to more accuracy of modeling. An EM type algorithm has considered for finding the maximum likelihood estimations of the model parameters. Modelling and prediction of infected numbers of COVID–19 in the U.S. has considered and vaccinated numbers of COVID–19 is considered as auxiliary (covariate) in the model.

Research paper thumbnail of Univariate and bivariate extensions of the generalized exponential distributions

Mathematica Slovaca, 2021

The main aim of this paper is to introduce a new class of continuous generalized exponential dist... more The main aim of this paper is to introduce a new class of continuous generalized exponential distributions, both for the univariate and bivariate cases. This new class of distributions contains some newly developed distributions as special cases, such as the univariate and also bivariate geometric generalized exponential distribution and the exponential-discrete generalized exponential distribution. Several properties of the proposed univariate and bivariate distributions, and their physical interpretations, are investigated. The univariate distribution has four parameters, whereas the bivariate distribution has five parameters. We propose to use an EM algorithm to estimate the unknown parameters. According to extensive simulation studies, we see that the effectiveness of the proposed algorithm, and the performance is quite satisfactory. A bivariate data set is analyzed and it is observed that the proposed models and the EM algorithm work quite well in practice.

Research paper thumbnail of Skewed Auto-Regressive Process with Exogenous Input Variables: An Application in the Administered Vaccine Doses on Covid-19 Spread

Fractals, 2022

This study focuses on the prevalence of COVID-19 disease along with vaccination in the United Sta... more This study focuses on the prevalence of COVID-19 disease along with vaccination in the United States. We have considered the daily total infected cases of COVID-19 with total vaccinated cases as exogenous input and modeled them using light/heavy tailed auto-regressive with exogenous input model based on the innovations that belong to the flexible class of the twopiece scale mixtures of normal (TP-SMN) family. We have shown that the prediction of COVID-19 spread is affected by the rate of vaccine injection. In fact, the presence of exogenous input variables in time series models not only increases the accuracy of modeling, but also causes better and closer approximations in some issues including predictions. An Expectation-Maximization (EM) type algorithm has been considered for finding the maximum likelihood (ML) estimations of the model parameters, and modelling as well as predicting the infected numbers of COVID-19 in the presence of the vaccinated cases in the U.S.

Research paper thumbnail of Robust clustering of COVID-19 cases across U.S. counties using mixtures of asymmetric time series models with time varying and freely indexed covariates

Journal of Applied Statistics, 2022

In this paper, we develop a mixture of autoregressive (MoAR) process model with time varying and ... more In this paper, we develop a mixture of autoregressive (MoAR) process model with time varying and freely indexed covariates under the flexible class of two–piece distributions using the scale mixtures of normal (TP-SMN) family. This novel family of time series (TP-SMN-MoAR) models was used to examine flexible and robust clustering of reported cases of Covid-19 across 313 counties in the U.S. The TP-SMN distributions allow for symmetrical/ asymmetrical distributions as well as heavy-tailed distributions providing for flexibility to handle outliers and complex data. Developing a suitable hierarchical representation of the TP-SMN family enabled the construction of a pseudo-likelihood function to derive the maximum pseudo-likelihood estimates via an EM-type algorithm.

Research paper thumbnail of رابطة کاهش درآمد، سلامت و خشنودی شغلی قبل از بازنشستگی با بهزیستی روانشناختی پس از آن با توجه به نقش تعدیلی وجود برنامه بازنشستگی، شغل در دوره گذار و انتظار بازنشستگی زودتر و دیرتر از انتظار

هدف این پژوهش، بررسی نقش تعدیلی سه متغیر برنامة بازنشستگی، مرحلة بازنشستگی و زمان بازنشستگی در را... more هدف این پژوهش، بررسی نقش تعدیلی سه متغیر برنامة بازنشستگی، مرحلة بازنشستگی و زمان بازنشستگی در رابطة بین کاهش درآمد، سلامت و خشنودی قبل از بازنشستگی با بهزیستی روان‌شناختی پس از آن است. روش پژوهش توصیفی رابطه‌ای است. جامعة آماری پژوهش، تمام کارکنان در معرض بازنشستگی در مجموعه‌ای از سازمان‌های صنعتی شهر اصفهان بوده است. برای سنجش فرضیات نمونه‌ای 893 نفری به روش در دسترس از کارکنان سازمان‌های اصفهان انتخاب شدند و به ابزارهای پژوهش شامل مقیاس CES-D (رادلف، 1977) و سؤالات مربوط به کاهش درآمد، سلامت، خشنودی شغلی قبل از بازنشستگی، همگی از پیمایش بازنشستگی و سلامت (HRS, 1992)، برنامه بازنشستگی و انتظار بازنشستگی وگلسنانگ (2014) پاسخ دادند. برای تحلیل داده‌ها از ضریب همبستگی و تحلیل زیرگروه‌ها برای تحلیل تعدیلی استفاده شد. نتایج نشان داد که رابطة بین خشنودی شغلی و بهزیستی قبل از بازنشستگی با بهزیستی روان‌شناختی بعد از بازنشستگی مثبت و رابطة بین فاصلة مورد انتظار تا بازنشستگی، گزارش فرد از کاهش سلامت و گزارش پزشکی کاهش سلامت با بهزیستی روان‌شناختی پس از بازنشستگی منفی است (01/0>P).

Research paper thumbnail of Archetypal Associations of Geometric Shapes: Lessons for Marketing Managers

‫مدیریت بازرگانی, 2018

The study seeks to identify how Iranian consumers (Isfahan as the case study) perceive archetypes... more The study seeks to identify how Iranian consumers (Isfahan as the case study) perceive archetypes. Drawing on the Theory of Shape Symbolism, the study also addresses geometric shapes as potential elements in conveying archetypal meaning to the brands. Findings from several preliminary studies and seventy-seven semi-structured in-depth interviews in the main study revealed that, in spite of some similarities, Isfahan citizens are somewhat different in their perception of archetypes compared to western consumers. Moreover, the most and the least fitting shape(s) with each archetype were identified. Respondents' archetypal associations with shapes are based on both intrinsic meaning stemming from shape's attributes such as symmetry, angularity and number of sides, and referential meaning of shapes. In contrast to the existing literature on geometric shapes, angularity is not the only shape characteristic to affect archetypal associations and is not proved influential in all arc...

Research paper thumbnail of On the Liu estimator in the beta and Kumaraswamy regression models: A comparative study

Communications in Statistics - Theory and Methods, 2021

Research paper thumbnail of The relation between quantum management skills and organizational agility capabilities with the mediating role of organizational intelligence

Research paper thumbnail of The Phenomenology of the Experience of Experts and Novice Managers in the Oil Industry to Identify Their Cognitive Differences

Research paper thumbnail of Double bounded Kumaraswamy-power series class of distributions

In this paper, we will introduce the new Kumaraswamy-power series class of distributions. This ne... more In this paper, we will introduce the new Kumaraswamy-power series class of distributions. This new class is obtained by compounding the Kumaraswamy distribution of Kumaraswamy (1980) and the family of power series distributions. The new class contains some new double bounded distributions such as the Kumaraswamy-geometric, -Poisson, -logarithmic and -binomial, which are used widely in hydrology and related areas. In addition, the corresponding hazard rate function of the new class can be increasing, decreasing, bathtub and upside-down bathtub. Some basic properties of this class of distributions such as the moment generating function, moments and order statistics are studied. Some special members of the class are also investigated in detail. The maximum likelihood method is used for estimating the unknown parameters of the members of the new class. Finally, an application of the proposed class is illustrated using a real data set.

Research paper thumbnail of The beta Weibull-geometric distribution

Journal of Statistical Computation and Simulation, 2013

ABSTRACT A new five-parameter distribution called the beta Weibull-geometric (BWG) distribution i... more ABSTRACT A new five-parameter distribution called the beta Weibull-geometric (BWG) distribution is proposed. The new distribution is generated from the logit of a beta random variable and includes the Weibull-geometric distribution of Barreto-Souza et al. [TheWeibull-geometric distribution, J. Stat. Comput. Simul. 81 (2011), pp. 645–657], beta Weibull (BW), beta exponential, exponentiated Weibull, and some other lifetime distributions as special cases. A comprehensive mathematical treatment of this distribution is provided. The density function can be expressed as an infinite mixture of BW densities and then we derive some mathematical properties of the new distribution from the corresponding properties of the BW distribution. The density function of the order statistics and also estimation of the stress–strength parameter are obtained using two general expressions. To estimate the model parameters, we use the maximum likelihood method and the asymptotic distribution of the estimators is also discussed. The capacity of the new distribution are examined by various tools, using two real data sets.

Research paper thumbnail of Double bounded Kumaraswamy-power series class of distributions

In this paper, we will introduce the new Kumaraswamy-power series class of distributions. This ne... more In this paper, we will introduce the new Kumaraswamy-power series class of distributions. This new class is obtained by compounding the Kumaraswamy distribution of Kumaraswamy (1980) and the family of power series distributions. The new class contains some new double bounded distributions such as the Kumaraswamy-geometric,-Poisson,-logarithmic and-binomial, which are used widely in hydrology and related areas. In addition, the corresponding hazard rate function of the new class can be increasing, decreasing, bathtub and upside-down bathtub. Some basic properties of this class of distributions such as the moment generating function, moments and order statistics are studied. Some special members of the class are also investigated in detail. The maximum likelihood method is used for estimating the unknown parameters of the members of the new class. Finally, an application of the proposed class is illustrated using a real data set. MSC: 60E05, 62E10.

Research paper thumbnail of The beta-Weibull geometric distribution

Statistics, 2011

We propose a new distribution, the so-called beta-Weibull geometric distribution, whose failure r... more We propose a new distribution, the so-called beta-Weibull geometric distribution, whose failure rate function can be decreasing, increasing or an upside-down bathtub. This distribution contains special sub-models the exponential geometric [K. Adamidis and S. Loukas, A lifetime distribution with decreasing failure rate, Statist. Probab. Lett. 39 (1998), pp. 35–42], beta exponential [S. Nadarajah and S. Kotz, The exponentiated type distributions, Acta Appl. Math. 92 (2006), pp. 97–111; The beta exponential distribution, Reliab. Eng. Syst. Saf. 91 (2006), pp. 689–697], Weibull geometric [W. Barreto-Souza, A.L. de Morais, and G.M. Cordeiro, The Weibull-geometric distribution, J. Stat. Comput. Simul. 81 (2011), pp. 645–657], generalized exponential geometric [R.B. Silva, W. Barreto-Souza, and G.M. Cordeiro, A new distribution with decreasing, increasing and upside-down bathtub failure rate, Comput. Statist. Data Anal. 54 (2010), pp. 935–944; G.O. Silva, E.M.M. Ortega, and G.M. Cordeiro, ...

Research paper thumbnail of The exponentiated discrete Weibull distribution

In this paper, the exponentiated discrete Weibull distribution is introduced. This new generaliza... more In this paper, the exponentiated discrete Weibull distribution is introduced. This new generalization of the discrete Weibull distribution can also be considered as a discrete analog of the exponentiated Weibull distribution. A special case of this exponentiated discrete Weibull distribution defines a new generalization of the discrete Rayleigh distribution for the first time in the literature. In addition, discrete generalized exponential and geometric distributions are some special sub-models of the new distribution. Here, some basic distributional properties, moments, and order statistics of this new discrete distribution are studied. We will see that the hazard rate function can be increasing, decreasing, bathtub, and upside-down bathtub shaped. Estimation of the parameters is illustrated using the maximum likelihood method. The model with a real data set is also examined.