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Showing 12 results for Subject:
Akbar Asgharzadeh, Mina Azizpour, Reza Valiollahi,
Volume 9, Issue 1 (9-2015)
Abstract
One of the drawbacks of the type II progressive censoring scheme is that the length of the experiment can be very large. Because of that, recently a new censoring scheme named as the type II progressively hybrid censored scheme has received considerable interest among the statisticians. In this paper, the statistical inference for the half-logistic distribution is discussed based on the progressively type II hybrid censored samples. The maximum likelihood estimator, the approximate maximum likelihood estimator and the Bayes estimator of parameter using Lindley approximation and MCMC method are obtained. Asymptotic confidence intervals, Bootstrap confidence intervals and Bayesian credible intervals are obtained. Different point and interval estimators are compared using Monte Carlo simulation. A real data set is presented for illustrative purposes.
Azadeh Kiapour, Mehran Naghizadeh Qomi,
Volume 10, Issue 2 (2-2017)
Abstract
In this paper, an approximate tolerance interval is presented for the discrete size-biased Poisson-Lindley distribution. This approximate tolerance interval, is constructed based on large sample Wald confidence interval for the parameter of the size-biased Poisson-Lindley distribution. Then, coverage probabilities and expected widths of the proposed tolerance interval is considered. The results show that the coverage probabilities have a better performance for the small values of the parameter and are close to the nominal confidence level, and are conservative for the large values of the parameter. Finally, an applicable example is provided for illustrating approximate tolerance interval.
Mehran Naghizadeh Qomi, Maryam Vahidian,
Volume 11, Issue 2 (3-2018)
Abstract
The problem of finding tolerance intervals receives very much attention in researches and is widely applied in industry. Tolerance interval is a random interval that covers a proportion of the considered population with a specified confidence level. In this paper, the statistical tolerance limits are expressed for lifetime of k out of n systems with exponentially distributed component lifetimes. Then, we compute the accuracy of proposed tolerance limits and the number of failures needed to attain a desired accuracy level based on type-II right censored data. Finally, we extend our results to the Weibull distribution.
Mehran Naghizadeh Qomi, Zohre Mahdizadeh, Hamid Zareefard,
Volume 12, Issue 1 (9-2018)
Abstract
Suppose that we have a random sample from one-parameter Rayleigh distribution. In classical methods, we estimate the interesting parameter based on the sample information and with usual estimators. Sometimes in practice, the researcher has some information about the unknown parameter in the form of a guess value. This guess is known as nonsample information. In this case, linear shrinkage estimators are introduced by combining nonsample and sample information which have smaller risk than usual estimators in the vicinity of guess and true value. In this paper, some shrinkage testimators are introduced using different methods based on vicinity of guess value and true parameter and their risks are computed under the entropy loss function. Then, the performance of shrinkage testimators and the best linear estimator is calculated via the relative efficiency of them. Therefore, the results are applied for the type-II censored data.
Masoumeh Akbari Lakeh, Zohreh Safarzadeh,
Volume 12, Issue 2 (3-2019)
Abstract
The Pareto distribution has many applications in economics and actuarial sciences. So far, a lot of properties of this distribution based on order data such as order statistics and records are studied. In this paper, a new version of notion of near-record observations is defined. Then, some results of characterization of Pareto distribution based on this new definition are obtained.
Mehrnaz Mohammadpour, Masoumeh Shirozhan,
Volume 14, Issue 1 (8-2020)
Abstract
In this paper, we introduce a new integer-valued autoregressive model of first order based on the negative binomial thinning operator, where the noises are serially dependent. Some statistical properties of the model are discussed. The model parameters are estimated by maximum likelihood and Yule-Walker methods. By a simulation study, the performances of the two estimation methods are studied. This survey was carried out to study the efficiency of the new model by applying it on real data.
Marjan Zare, Akbar Asgharzadeh, Seyed Fazel Bagheri,
Volume 14, Issue 1 (8-2020)
Abstract
In this paper, the smallest confidence region is obtained for the location and scale parameters of the two-parameter exponential distribution. For this purpose, we use constrained optimization problems. We first provide some suitable pivotal quantities to obtain a balanced confidence region. We then obtain the smallest confidence region by minimizing the area of the confidence region using the Lagrangian method. Two numerical examples are presented to illustrate the proposed methods. Finally, some applications of proposed joint confidence regions in hypothesis testing and the construction of confidence bands are discussed.
Mehran Naghizadeh Qomi,
Volume 14, Issue 2 (2-2021)
Abstract
In classical statistics, the parameter of interest is estimated based on sample information and using natural estimators such as maximum likelihood estimators. In Bayesian statistics, the Bayesian estimators are constructed based on prior knowledge and combining with it sample information. But, in some situations, the researcher has information about the unknown parameter as a guess. Bayesian shrinkage estimators can be constructed by Combining this non-sample information with sample information together with the prior knowledge, which is in the area of semi-classical statistics. In this paper, we introduce a class of Bayesian shrinkage estimators for the Weibull scale parameter as a generalization of the estimator at hand and consider the bias and risk of them under LINEX loss function. Then, the proposed estimators are compared using a real data set.
Firozeh Bastan, Seyed Mohamad Taghi Kamel Mirmostafaee,
Volume 15, Issue 2 (3-2022)
Abstract
In this paper, estimation and prediction for the Poisson-exponential distribution are studied based on lower records and inter-record times. The estimation is performed with the help of maximum likelihood and Bayesian methods based on two symmetric and asymmetric loss functions. As it seems that the integrals of the Bayes estimates do not possess closed forms, the Metropolis-Hastings within Gibbs and importance sampling methods are applied to approximating these integrals. Moreover, the Bayesian prediction of future records is also investigated. A simulation study and an application example are presented to evaluate and show the applicability of the paper's results and also to compare the numerical results when the inference is based on records and inter-record times with those when the inference is based on records alone.
Alla Alhamidah, Mehran Naghizadeh, ,
Volume 16, Issue 2 (3-2023)
Abstract
This paper discusses the Bayesian and E-Bayesian estimators in Burr type-XII model is discussed. The estimators are obtained based on type II censored data under the bounded reflected gamma loss function. The relationship between E-Bayesian estimators and their asymptotic properties is presented. The performance of the proposed estimators is evaluated using Monte Carlo simulation.
Doctor Masoumeh Akbari, Mrs Arefeh Kasiri, Doctor Kambiz Ahmadi,
Volume 17, Issue 1 (9-2023)
Abstract
In this paper, quantile-based dynamic cumulative residual and failure extropy measures are introduced. For a presentation of their applications, first, by using the simulation technique, a suitable estimator is selected to estimate these measures from among different estimators. Then, based on the equality of two extropy measures in terms of order statistics, symmetric continuous distributions are characterized. In this regard, a measure of deviation from symmetry is introduced and how it is applied is expressed in a real example. Also, among the common continuous distributions, the generalized Pareto distribution and as a result the exponential distribution are characterized, and based on the obtained results, the exponentiality criterion of a distribution is proposed.
Mehran Naghizadeh Qomi, Zohre Mahdizadeh,
Volume 19, Issue 1 (9-2025)
Abstract
This paper investigates repetitive acceptance sampling inspection plans of lots based on type I censoring when the lifetime has a Tsallis q-exponential distribution. A repetitive acceptance sampling inspection plan is introduced, and its components, along with the optimal average sample number and the operating characteristic value of the plan, are calculated under the specified values for the parameter of distribution and consumer's and producer's risks using a nonlinear programming optimization problem. Comparing the results of the proposed repetitive acceptance sampling plan with the optimal single sampling inspection plan demonstrates the efficiency of the repetitive acceptance sampling plan over the single sampling plan. Moreover, repetitive sampling plans with a limited linear combination of risks are introduced and compared with the existing plan. Results of the introduced plan in tables and figures show that this plan has a lower ASN and, therefore, more efficiency than the existing design. A practical example in the textile industry is used to apply the proposed schemes.
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