Balanced 2m factorial designs of resolution v which allow search and estimation of one extra unknown effect, 4 ≤ m ≤ 8

In this paper, we obtain balanced resolution V plans for 2^m factorial experiments (4 ≤ m ≤ 8), which have an additional feature. Instead of assuming that the three factor and higher order effects are all zero, we assume that there is at most one nonnegligible effect among them; however, we do not know which particular effect is nonnegligible. The problem is to search which effect is non-negligible and to estimate it, along with estimating the main effects and two factor interactions etc., as in an ordinary resolution V design. For every value of N (the number of treatments) within a certain practical range, we present a design using which the search and estimation can be carried out. (Of course, as in all statistical problems, the probability of correct search will depend upon the size of “error” or “noise” present in the observations. However, the designs obtained are such that, at least in the noiseless case, this probability equals 1.) It is found that many of these designs are identical with optimal balanced resolution V designs obtained earlier in the work of Srivastava and Chopra.     

Comparison of powers for the sphericity tests using both the asymptotic distribution and the bootstrap

The asymptotic distributions of two tests for sphericity:the locally most powerful invariant test and the likelihood ratio test are derived under the general alternaties ∑?σ² I. The powers of these two tests are then compared when the data are from a trivariate normal population. The bootstrap method is also used to obtain the powers and the powers obtained by this method agree with those from the asymptotic distributions.     

Asymptotic confidence interval of power spectrum of a continuous time process through progressively faster sampling

If the power spectral density of a continuous time stationary stochastic process is not limited to a finite bandwidth, data sampled from that process at any uniform sampling rate leads to biased and inconsistent spectrum estimators, which are unsuitable for constructing confidence intervals. In this paper, we use the smoothed periodogram estimator to construct asymptotic confidence intervals shrinking to the true spectra, by allowing the sampling rate to go to infinity suitably fast as the sample size goes to infinity. The proposed method requires minimal computation, as it does not involve bootstrap or other resampling. The method is illustrated through a Monte-Carlo simulation study, and its performance is compared with that of the corresponding method based on uniform sampling at a fixed rate.     

Comparison of some linear calibration estimators

In this article, we consider a family of linear calibration estimators arising from inverse estimator and analyze its properties employing the small disturbance asymptotic theory. The asymptotic approximations for bias and mean squared error of this family are compared with the corresponding results for classical and inverse estimators, whose properties are also compared.     

Advances in the statistical theory of comparison of lifetimes of machines under the generalized weibull distribution

Some new censoring schemes for comparing lifetimes of machines were introduced in Srivastava (1987), wherein it was shown that in general, these improve on the accuracy and also reduce the total expected time under experiment as well as the expected length of the experiment. Although the above studies were initiated under the generalized WeibuU distribution, the detailed development of the theory for the expected time or length were made under the Weibull only. In this paper, for a certain important special case, this development is extended to the generalized Weibull. Also, an error in the above paper is pointed out, and corrected, showing that the new schemes are actually superior to what they appeared to be there. Furthermore, under a realistic cost function, the problem of planning such experiments is discussed. An example for machines with a series connection is provided.     

Pitman nearness comparisons of Stein-type estimators for regression coefficients in replicated experiments

This paper presents a comparative study of the performance properties of one unbiased and two Stein-type estimators for combining the estimates of coefficients in a linear regression model when data sets are available from replicated experiments conducted at possibly different stations.     

Health care reform. Pan American Uni-Care Health Insurance Plan

Something is definitely wrong with the American health care system. Too many citizens are denied health care, and health care costs continue to rise at an uncomfortable and intolerable rate. Ensuring care for all is a paramount goal. There is no way to simultaneously cover everyone; leave the reimbursement of physicians unrestrained; ensure instantaneous access to every imaginable high-technology service; subsidize the world's costliest and least efficient health bureaucracy; and contain costs. Widespread dissatisfaction in all quarters--physicians, hospitals, third-party payers, regulators and consumers--has led to an avalanche of reform proposals. Rapidly changing social, political, and economic environments; rising fiscal pressure; and an evolving understanding of the major determinants of health have also created pressure for changes. There are some new and hopeful signs that America is facing up to the need for changes in the health care delivery system. The Pan American Uni-Care Health Plan that is described in this article may serve as a reasonable balance among these competing priorities.     

Green supply‐chain management: A state‐of‐the‐art literature review

There is a growing need for integrating environmentally sound choices into supply‐chain management research and practice. Perusal of the literature shows that a broad frame of reference for green supply‐chain management (GrSCM) is not adequately developed. Regulatory bodies that formulate regulations to meet societal and ecological concerns to facilitate growth of business and economy also suffer from its absence. A succinct classification to help academicians, researchers and practitioners in understanding integrated GrSCM from a wider perspective is needed. Further, sufficient literature is available to warrant such classification. This paper takes an integrated and fresh look into the area of GrSCM. The literature on GrSCM is covered exhaustively from its conceptualization, primarily taking a ‘reverse logistics angle’. Using the rich body of available literature, including earlier reviews that had relatively limited perspectives, the literature on GrSCM is classified on the basis of the problem context in supply chain's major influential areas. It is also classified on the basis of methodology and approach adopted. Various mathematical tools/techniques used in literature vis‐à‐vis the contexts of GrSCM are mapped. A timeline indicating relevant papers is also provided as a ready reference. Finally, the findings and interpretations are summarized, and the main research issues and opportunities are highlighted.     

Selection buasubg parameters in adaptive ridge regression estimators

Strawderman's family of regression estimators is considered. The choice of the scalars wbich characterize the biasing parameter is studied by obtaining the bias vector and the mean squared error matrix.