On location and scale parameters of exponential distributions with censored observations

In this paper we first address the problem of estimating the common scale of several exponential distributions with unknown location parameters when censored samples are observed. The improved estimators are basically Stein type testimators. These testimators are then used to construct improved estimators of location parameters.     

Estimation of the smaller and larger of two uniform scale parameters

Assume independent random samples are drawn from two populations which are uniformly distributed with unknown scale parameters. The problem is to estimate the minimum and the maximum of the two unknown scales. In this paper, several simple estimators are proposed which are better than the natural estimators in terms of standardized bias, risk under squared error loss and the Pitman nearness criterion.     

Estimation of a normal variance—A critical review

Consider the problem of estimating the variance based on a random sample from a normal distribution with unknown mean. In this article we review the rich literature developed over the last three decades on the problem of variance estimation in a decision theoretic setup. While examining the developments we point out a few errors that exist in the literature.     

Causes of death contributing to changes in life expectancy in New York City between 1983 and 1992

Recent changes in life expectancy among race and sex groups in New York City were evaluated by analyzing the relative effects of different causes of death in 1983 and 1992, a period in which life expectancy at birth declined by 1.1 years among white males, remained unchanged among black males, and increased 1.2 years among white and black females. Heart disease was found to be the leading cause of death making positive contributions to changes in life expectancy regardless of race or sex, and HIV/AIDS was the leading negative contributor. Overall, deaths from infectious diseases and external causes are becoming more important compared to degenerative conditions in explaining trends in life expectancy in New York City. Past improvements in survival due to reductions in infant deaths are being reversed due to an increase in deaths from preventable causes such as violence and AIDS. Future gains in longevity may require a greater emphasis on policies and programs emphasizing conflict resolution and HIV prevention.     

A family of efficient estimators of the finite population mean in simple random sampling

In this paper an estimator of the finite population mean using auxiliary information in sample surveys has been proposed. The bias and mean squared error are obtained under large sample approximation. It has been shown that the proposed estimator performs better than some recently published estimators.