On an adaptive transformation–retransformation estimate of multivariate location

An affine equivariant estimate of multivariate location based on an adaptive transformation and retransformation approach is studied. The work is primarily motivated by earlier work on different versions of the multivariate median and their properties. We explore an issue related to efficiency and equivariance that was originally raised by Bickel and subsequently investigated by Brown and Hettmansperger. Our estimate has better asymptotic performance than the vector of co-ordinatewise medians when the variables are substantially correlated. The finite sample performance of the estimate is investigated by using Monte Carlo simulations. Some examples are presented to demonstrate the effect of the adaptive transformation–retransformation strategy in the construction of multivariate location estimates for real data.     

Coefficient of variation for the L-class of life distributions

It is shown that the coefficient of variation for the L-class of life distributions is less than or equal to 1.We prove that a d.f. F, belonging to the L-class of life distributions , is exponential if and only if its coefficient of variation is equal to 1.     

On the Feasibility of Basing Horvitz and Thompson's Estimator on a Sample by Rao,Hartley, and Cochran's Scheme

Formulae for the first and second order inclusion probabilities for the Rao et al. (1962 Rao , J. N. K. , Hartley , H. O. , Cochran , W. G. ( 1962 ). On a simple procedure of unequal probability sampling without replacement . J. Roy. Statist. Soc. B 24 : 482 – 491 . [CSA]  [Google Scholar]) (RHC) scheme of sampling are derived. They enable one to evaluate, for a sample drawn according to the RHC scheme, the Horvitz and Thompson's (1952 Horvitz , D. G. , Thompson , D. J. ( 1952 ). A generalization of sampling without replacement from a finite universe . J. Amer. Statist. Assoc. 47 : 663 – 685 . [CSA] [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]) estimator (HTE) along with its unbiased variance estimator given by Yates and Grundy (1953 Yates , F. , Grundy , P. M. ( 1953 ). Selection without replacement from within strata with probability proportional to size . J. Amer. Statist. Assoc. 75 : 206 – 211 . [CSA]  [Google Scholar]). So, for a sample at hand thus drawn one may choose between the RHCE and the HTE for use on finding which one has the smaller coefficient of variation.     

Spillover Impacts of a Reproductive Health Program on Elderly Women in Rural Bangladesh

This paper extends the program evaluation literature by investigating intra-household externalities generated by a reproductive health program, administered as a quasi-control experiment in rural Bangladesh. Although the program targeted only mothers and children in randomly selected treatment areas, using a reduced form demand approach and data from Matlab Health and Socio-economic Survey of 1996, we found a significantly positive spillover impact of this reproductive health program on the health of the never-targeted elderly women.

Production lot sizing with process deterioration and machine breakdown under inspection schedule

The paper develops integrated production, inventory and maintenance models for a deteriorating production system in which the production facility may not only shift from an ‘in-control’ state to an ‘out-of-control’ state but also may break down at any random point in time during a production run. In case of machine breakdown, production of the interrupted lot is aborted and a new production lot is started when the on-hand inventory is depleted after corrective repair. The process is inspected during each production run to examine the state of the production process. If it is found in the ‘in-control’ state then either (a) no action is taken except at the time of last inspection where preventive maintenance is done (inspection policy-I) or (b) preventive maintenance is performed (inspection policy-II). If, however, the process is found to be in the ‘out-of-control’ state at any inspection then restoration is done. The proposed models are formulated under general shift, breakdown and repair time distributions. As it is, in general, difficult to find the optimal production policy under inspection policy-I, a suboptimal production policy is derived. Numerical examples are taken to determine numerically the optimal/suboptimal production policies of the proposed models, to examine the sensitivity of important model parameters and to compare the performance of inspection and no inspection policies.     

A finite population quantile estimation by unequal probability sampling

Abstract

Using a model-assisted approach, this paper studies asymptotically design-unbiased (ADU) estimation of a population “distribution function” and extends to deriving an asymptotic and approximate unbiased estimator for a population quantile from a sample chosen with varying probabilities. The respective asymptotic standard errors and confidence intervals are then worked out. Numerical findings based on an actual data support the theory with efficient results.     

On the bias and mean-square error of order-restricted maximum likelihood estimators

The inverse Gaussian family (IG) (μ,λ) is a versatile family for modelling nonnegative right-skewed data. In this paper, we propose robust methods for testing homogeneity of the scale-like parameters λ_i from k independent IG populations subject to order restrictions. Robustness of the procedures is examined for a variety of IG-symmetric alternatives including lognormal and the recently introduced contaminated inverse Gaussian populations. Our study shows that these inference procedures for the inverse Gaussian scale-like parameters and their properties exhibit striking similarities to those of the scale parameters of the normal distribution.     

The Many Faces of a Neutral Face: Head Tilt and Perception of Dominance and Emotion

Based on the premise that human head tilt is homologous to animal dominance displays, we hypothesized that when a head is bowed, the face should be perceived as submissive, sad, displaying inferiority emotions (i.e., shame, embarrassment, guilt, humiliation, and respect) and, paradoxically, as contracting the zygomatic major muscle. Conversely, a raised head should be perceived as more dominant and displaying greater superiority emotions (i.e., contempt and pride). We conducted two experiments showing 3-D models of faces to 64 participants. The results confirmed our hypotheses and also showed that a raised head connotes happiness. In addition, we found a significant influence of the actors' sex on participants' perception, such as a bias towards perceiving stronger upward contraction of the mouth in female than male actors when the head is tilted. We discuss these findings within the context of evolution and social behavior.     

A New Perspective on Violent Crime Burden Index: Evidence from Indian Districts

Given limited resource availability in a developing nation like India, faced with high incidences of crime, it is important to optimize on the resources spent in combating crime by channelling them to proper direction. This requires an understanding of the actual and overall level of crime across India. Our paper provides a complete understanding of the various indicators of violent crime and the determinants of these crimes in India using district level data for three census years, namely, 1981, 1991 and 2001. We construct three alternative crime-burden indices. Including a variable like voter turnout in state election at the district level, we document significant impact of public awareness to reduce and combat crime. The constructed crime burden index shows that states located in northern parts of India have more incidences of crime compared to states in the south. We also find that our estimated crime-burden indices tend to report in general a higher level of crime-burden than the average based index. This suggests controlling for the factors beyond population while constructing the aggregate crime-burden index for any country is essential. Our work although is limited to the Indian data, we however, believe that this can be easily applied to various other countries.