Showing papers in "Calcutta Statistical Association Bulletin in 2007"
TL;DR: In this paper, a very flexible family which contains the gamma distrihution as a particular case is introduced, and the gamma distribution is used to model hydrological processes.
Abstract: Gamma distributions are some of the most popular models for hydrological processes. In this paper, a very flexible family which contains the gamma distrihution as a particular case is introduced. T...
90 citations
TL;DR: In this article, the authors studied another equivalent characterization of the reversed hazard rate along with its bivariate extensions and characterized a class of distributions having constant rhr in its interval of support.
Abstract: Block et.al (1998) studied the properties of the reversed hazard rate (rhr) and characterized a class of distributions having constant rhr in its interval of support. In this paper we study another equivalent characterization of this class along with its bivariate extensions.
8 citations
TL;DR: In this paper, a single item inventory model for deteriorating items, where the permissible delay in payment depends on the ordered quantity and shortages are partially backlogged, assuming the backlogging rate to be inversely proportional to the waiting time for the next replenishment, is presented.
Abstract: Abstract: In many inventory situations, instead of making immediate payment on receiving the consigument, the purchaser is allowed a certain fixed time period to pay for the goods bought. During this time the supplier charges no interest, but beyond this period interest is charged under the terms and condition agreed upon. As for the purchaser, he can earn interest on the revenue coolected during the credit period. This paper studies a single item inventory model for deteriorating items, when the permissible delay in payment depends on the ordered quantity and shortages are partially backlogged, assuming the backlogging rate to be inversely proportional to the waiting time for the next replenishment. An algorithm has been developed to find the optimal inventory policy. Numerical examples have been cited to illustrate the model. AMS (2000) Subject Classification: 90B05.
5 citations
TL;DR: In this paper, a necessary and sufficient condition for a nested block design to be trend-free at sub-block level is derived, and families and catalogues of NBIB designs that can be converted into trendfree optimal block designs for diallel cross experiments are also obtained.
Abstract: Abstract: Nested balanced incomplete block (NBIB) designs are useful when the experiments are conducted to deal with experimental situations when one nuisance factor is nested within the blocking factor. Similar to block designs, trend may exist in experimental units within sub‐blocks or within blocks in NBIB designs over time or space. A necessary and sufficient condition, for a nested block design to be trend‐free at sub‐block level, is derived. Families and catalogues of NBIB designs that can be converted into trend‐free NBIB designs at sub‐block and block levels have been obtained. A NBIB design with sub‐block size 2 has a one to one correspondence with designs for diallel crosses experiments. Therefore, optimal block designs for dialled cross experiments have been identified to check if these can be converted in to trend‐free optimal block designs for diallel cross experiments. A catalogue of such designs is also obtained. Trend‐free design is illustrated with example for a NBIB design and a design for diallel crosses experiments. AMS (2000) Subject Classification: 62K05, 62K10.
3 citations
TL;DR: As hazard function, the role of reversed hazard rate function is well known in reliability analysis and is useful in the analysis of left censored lifetime data as well as in the study o... as mentioned in this paper.
Abstract: As hazard function, the role of reversed hazard rate function is well known in reliability analysis. This function is useful in the analysis of left censored lifetime data as well as in the study o...
3 citations
TL;DR: In this article, the authors defined affinity for truncated distributions and examined its properties, and provided a characterization result for the proportional hazard model using the functional form of the truncated affinity.
Abstract: Abstract: In the present paper we define affinity for truncated distributions and examine its properties. The relationship of this measure with other discrimination measures is examined. We also provide a characterization result for the proportional hazard model using the functional form of the truncated affinity. AMS (2000) Subject Classification: 62E10, 90B25
3 citations
TL;DR: In this paper some constructions of the Pencilwise Orthogonal and Balanced Designs of Das (2001), mainly based on difference and composition methods, are given.
Abstract: In this paper some constructions of the Pencilwise Orthogonal and Balanced Designs of Das (2001), mainly based on difference and composition methods, are given.
2 citations
TL;DR: In this paper, the authors present formulae applicable to general varying probability sampling, even without replacement applying Takahasi and Sakasegawa device, and demonstrate that they can be used to estimate proportions of people bearing sensitive characteristics.
Abstract: Abstract: Randomized Response (RR) Technique (RRT), introduced by Warner (1965), is a well‐known way to unbiasedly estimate proportions of people bearing sensitive characteristics. Takahasi and Sakasegawa (1977) narrated a novel procedure avoiding any particular RR device unlike most researchers in this field. Most RRT’s in the literature give estimators for population totals and variance estimators thereof, allowing exclusively simple random sampling with replacement (SRSWR) schemes, including as well the above too. We present formulae applicable to general varying probability sampling, even without replacement applying Takahasi‐ Sakasegawa device. AMS (2000) Subject Classification: 62D05.
1 citations
TL;DR: In this paper, the authors derived an expression for the maximum value of the probability of correct searching for a supersaturated design for a given run size, assuming that there is only one active factor present in the model.
Abstract: Abstract: In this paper we have argued that the probability of correct searching is a more acceptable criterion for comparing two competitive supersaturated designs. We have derived an expression for the maximum value of the probability of correct searching for a supersaturated design for a given run size, assuming that there is only one active factor present in the model. We have also provided a result pertaining to the maximum number of factors that can be accommodated with a given value of probability of correct searching and with a particular run size. Finally an algorithm for constructing probability optimal supersaturated designs is presented. The performance of the designs constructed are also evaluated, in terms of the probability of correct search in stituations involving the presence of two active factors, using a simulation study. AMS (2000) Subject Classification: 62K05, 62K15.
1 citations
TL;DR: In this article, the authors considered the problem of convergence of an estimator T n of the unknown parameter θ ε R to a finite end point of the distribution function, and obtained a confidence interval for θ with highest coverage probability 1 for all sufficiently large n.
Abstract: Abstract: An estimator T n of the unknown parameter θ ε R is said to converge to θ from above (below), if T n ≥ θ (T n ≤ θ) for all sufficiently large sample size n and T n → θ a.s., as n → ∞. Estimation problems of this kind are considered when θ is a finite end point of the distribution function. Confidence interval for θ with highest coverage probability 1, for all sufficiently large n is obtained. Applications to real data sets including industrial data and sea tide data are made. AMS (2000) Subject Classification: Primary 60F15, Secondary 62G32.
1 citations
TL;DR: In this paper, an expression for the bias associated with maximum likelihood estimates of the parameters in a multivariate generalized linear model (MGLM) is derived, which can be used as a criterion for comparing response surface designs for a MGLM.
Abstract: In this article, an expression is derived for the bias associated with maximum likelihood estimates of the parameters in a multivariate generalized linear model (MGLM). This expression represent.s an extension of the bias formula in the case of a univariate generalized linear model. One important objective of the proposed extension is to obtain an expression for the mean squared error of prediction matrix, which can be used as a criterion for comparing response surface designs for a MGLM. An application of the bias formula is presented in the special case of the bivariate binary distribution. A numerical example is given to illustrate this particular application.
TL;DR: In this article, the authors presented step-stress accelerated life test for the Pareto distribution with type I censoring, where the maximum likelihood estimates (MLE), Fisher information matrix and hence the variance-covariance matrix of the parameters were derived in closed form.
Abstract: This paper presents stepstress accelerated life test for the Pareto distribution with type I censoring. It is assumed that Pareto scale parameter depends on the stress variable and the shape parameter remains constant. It is also assumed that failures occur according to a cumulative exposure modcl(CEM) by Nelson (1990). On the basis of this model we describe maximum likelihood estimation proceuure and expression of the Fisher information matrix has been derived in closed form. A simulation study has been done to obtain the maximum likelihood estimates(MLE), Fisher information matrix and hence the variancecovariance matrix of the parameters. For selected values of the rlesign parameters the optimum low stress as well as the stress change time are obtained which minimize the asymptotic variance of the MLE of a stated percentile.