Some results on maximum likelihood estimators of parameters of exponential distribution under type I progressive censoring with changing failure rates

In this paper the study of relative bias (RB), exact variance and mean square error (MSE) of the maximum likelihood estimators of the exponential distribution under type I progressive censoring with changing failure rates is considered. A minimum mean square error (MMSE) estimator for the parameter at each stage is proposed. The numerical evalution of their relative performance is made for selected values of n and p. Further results concerning group-censoring, total expected waiting time and optimal spacings of the times of censoring are derived and results obtained by Kendell and Anderson (1971) are deduced as special cases.     

Causes and outcomes in studies of fear of childbirth: A systematic review

Problem

Fear of childbirth negatively affects women during pregnancy and after birth.

Domestic group,status of women,and fertility

An attempt is made in this paper to explain the fertility behavior of Patels; a major peasant caste in village Mogra in Rajasthan, India. The Patels make up 162 of the 404 households in the village and nearly 50% of the village's population of 2610. The Patels claim to have migrated from Gujarat a few centuries ago. This paper is based on a study of 140 randomly selected Patel households comprising 168 couples by using the method of intensive fieldwork over a period of about 6 months. Every household in Mogra, with the possible exception of 1 household of a Bania trader, is involved in agriculture in 1 capacity or another. The Patels are the major landowning caste, and all but 2 of the households in the sample of 140 own land. The Patels marry early, and the practice of child marriage remains common today. Being a patrilineal people, Patels consider sons as heirs to family property and status. Of the 140 households in the sample, 65 are complex in composition while 75 are simple. All the simple households are consequences of the partition of complex households. The consummation of marriage marks an immediate loss of independence to the woman. The Patels of Mogra have sound economic reasons for having a large number of children. They prefer to use family labor to the maximum possible extent. When labor is the major input, the land can absorb whatever labor is available. A great demand exists for labor in the domestic sphere as well. Compared to the returns, the cost of bringing up children is negligible. The expenditure on their clothing and education is minimal. Economics alone do not explain high fertility. Sons are essential to continue the line and for old age security. The marriage of daughters brings in bride price and religious merit. 1 son may find the burden of carrying out the kinship obligations inherited from his parents too high. When there are several sons, they can share the burden among themselves. Religious values and the obligations of kinship and marriage impel couples toward large families. It is this conjunction of forces rather than any single factor which is crucial. All these forces find expression in interpersonal relations within the family. The young mother is the person most interested in restricting births, but she is also interested in the additional labor supply that children would bring in. It is difficult for her to carry the load of domestic and farm work, childbearing and child rearing. When her reproductive career is at the peak, the woman's own power within the domestic group is at its lowest. It is through the process of giving birth to many children that she gains in power and status.     

Interval estimation of the largest reliability of k weibull populations

A procedure is given for obtaining a random width confidence interval for the largest reliability of k Weibull populations. The procedure does not identify the populations for which the reliability would be a maximum. The maximum likelihood estimators or the simplified linear estimators of the reliability based on type II censored data are used. The cases considered include unknown shape parameters being equal or unequal. Simultaneous confidence intervals for the k reliabilities are also obtained. Tables for the lower and upper limits in selected cases are constructed using Monte Carlo methods.     

On multistage group screening designs

In this article we discuss multistage group screening in which group-factors contain differing number of factors. We describe a procedure for grouping the factors in the absence of concrete prior information, so that the relative testing cost is minimal. It Is shown that under quite general conditions, these designs will require fewer runs than the equivalent designs in which the group-factors contain same number of factors.     

On selecting populations better than a control: weibull populations case

Consider k( k ≥ 1) independent Weibull populations and a control population which is also Weibull. The problem of identifying which of these k populations are better than the control using shape parameter as a criterion is considered. We allow the possibility of making at most m(0 ≤ m < k) incorrect identifications of better populations. This allowance results in significant savings in sample size. Procedures based on simple linear unbiased estimators of the reciprocal of the shape parameters of these populations are proposed. These procedures can be used for both complete and Type II-censored samples. A related problem of confidence intervals for the ratio of ordered shape parameters is also considered. Monte Carlo simulations as well as both chi-square and normal approximations to the solutions are obtained.     

Selecting the best one of several meifull populations

Consider k(k ≥ 2) two-parameter Meibull populations. Using type II censored data we want to select a best population. Me have proposed procedures which can be used for maximum likelihood estimators or simplified linear estimators of Che unknown parameters. The ranking of the populations is done by comparing their reliabilities at certain fixed time or by comparing their 2-eh quantiles. In selected cases, the constants needed for the procedures are tabulated using Monte Carlo methods.     

Reconfiguration graphs for vertex colourings of chordal and chordal bipartite graphs

A k-colouring of a graph G=(V,E) is a mapping c:V→{1,2,…,k} such that c(u)≠c(v) whenever uv is an edge. The reconfiguration graph of the k-colourings of G contains as its vertex set the k-colourings of G, and two colourings are joined by an edge if they differ in colour on just one vertex of G. We introduce a class of k-colourable graphs, which we call k-colour-dense graphs. We show that for each k-colour-dense graph G, the reconfiguration graph of the ?-colourings of G is connected and has diameter O(|V|²), for all ?≥k+1. We show that this graph class contains the k-colourable chordal graphs and that it contains all chordal bipartite graphs when k=2. Moreover, we prove that for each k≥2 there is a k-colourable chordal graph G whose reconfiguration graph of the (k+1)-colourings has diameter Θ(|V|²).     

Longing for Mourning

“Longing for Mourning” is a meditation on the verities of events that establish the ostensible stability of supposedly ordinary relationships—commitment, house-buying, and marriage. Influenced by the long history of meditations and commentarial literature on loss and aesthetics, this biographical essay is written as an aesthetic embodiment of theoretical positions. It ruminates on the forms through which time, death, loss, and repeated mourning transform such verities when they are the life story of an interracial, interclass, transcontinental and transnational relationship between two women.