The heritability of emergent leadership: Age and gender as moderating factors

In this study, we examined the moderating influences of gender and age with respect to testing the heritability of leadership emergence. A large data base of 12,112 twins from Sweden was used in the current study to decompose the variance of emergent leadership into an unobservable genetic component and environmental components that are either common or unshared among twin pairs. Consistent with prior leadership research on genetics, we found that a genetic factor is able to explain a significant proportion of the variation across individuals in predicting how twins perceive their emergent leadership behavior (about 44% for women and 37% for men). Furthermore, we also found that the magnitude of genetic influence on emergent leadership varied with age, but only for women with the heritability estimate being highest for the mid-age women versus lowest for the older women. Implications for advancing research on the genetic and environmental influences on leadership emergence are discussed.     

Second-Order Approximations to Two Classes of Sequential Estimation Procedures

For the model considered by Chaturvedi, Pandey and Gupta (1991), two classes of sequential procedures are developed to construct confidence regions (which may be interval, ellipsoidal or spherical) of ‘pre-assigned width and coverage probability’ for the parameters of interest and for the minimum risk point estimation (taking loss to be quadratic plus linear cost of sampling) of the nuisance parameter. Second-Order approximations are derived for the expected sample size, coverage probability and ‘regret’ associated with the two classes of sequential procedures. A simple and direct method of obtaining the asymptotic distribution of the stopping time is provided. By means of examples, it is illustrated that several estimation problems can be tackled with the help of proposed classes of sequential procedures.     

On some consistent tests of mutual independence among several random vectors of arbitrary dimensions

Statistics and Computing - Testing for mutual independence among several random vectors is a challenging problem, and in recent years, it has gained significant attention in statistics and machine...     

Of peasants and publics in colonial India: Daduram's story

ABSTRACT

This article uses an exceptionally well-documented law case from the 1650s to offer a fresh perspective on the English experience of Atlantic settlement during its early years. It argues for the centrality of the Essex county quarter sessions court in the building of neighbourhood on the geographic and cultural margins of the Massachusetts Bay colony. By focusing on the north-eastern margin at Cape Ann, the analysis reveals aspects of state building through a common law judicial process which was just as important, but less readily apparent, in other settings. The article addresses three major historiographic areas, engaging with the historical literature on English neighbourhoods and English adaptation to the American environment, on the significance of witchcraft or maleficium in English societies, and on the nature and meanings of law, law courts and judicial process in the building of communities. Case documents also enable the use of some concepts and techniques of literary analysis related to the study of narrative, arguing that judicial verdicts selected and suppressed aspects of local stories elicited during the course of the investigation in order to craft an account of local neighbourhood that suited a broader cultural narrative of Massachusetts Bay’s political consolidation during the 1650s.     

Bayesian estimation for the Pareto income distribution

The Bayes estimators of the Gini index, the mean income and the proportion of the population living below a prescribed income level are obtained in this paper on the basis of censored income data from a pareto income distribution. The said estimators are obtained under the assumptions of a two-parameter exponential prior distribution and the usual squared error loss function. This work is also extended to the case when the income data are grouped and the exact incomes for the individuals in the population are not available. The method for the assessment of the hyperparameters is also outlined. Finally, the results are generalized for the doubly truncated gamma prior distribution. Now deceased.     

An econometric analysis of the U.S. postwar G.N.P.

Whilst most developed countries have experienced stable economic conditions during the postwar period, the acceptance of the unit root null hypothesis implies wild fluctuations in the major economic variables over time. This paper investigates the sensitivity of the decisions to accept the unit root hypothesis to the specification of the trends underlying the U.S. postwar GNP and other macro-variables. In particular, the relationship between the nominal GNP and the resident population is found to be a non-linear one. The unit root null hypothesis can be firmly rejected when the conditional mean of the nominal GNP series is represented by a quadratic trend variable and the assumptions that changes in the price level and the resident population lead to equiproportionate changes in the GNP are not enforced on the data. The case of quarterly observations is also investigated for seasonally unadjusted and adjusted data.The author is indebted to two anonymous referees and the Managing Editor for helpful comments.     

Safety Stock,Excess Capacity or Diversification: Trade‐Offs under Supply and Demand Uncertainty

Firms mitigate uncertainty in demand and supply by carrying safety stock, planning for excess capacity and diversifying supply sources. In this study, we provide a framework to jointly optimize these three levers in a periodic review infinite horizon setting, and in particular we examine how one can reduce inventory and capacity investments through proper diversification strategies. Observing that a modified base‐stock inventory policy is optimal, we find that the capacity‐diversification problem is well behaved and characterize the optimal mix of safety stock, excess capacity and extra number of supply sources. We find that higher supply uncertainty results in higher safety stock, more excess capacity, and higher diversification. But safety stock and diversification are non‐monotonic in demand uncertainty. Our results can be extended to situations in which suppliers are heterogeneous, and can be used to develop effective heuristics.     

Ridge regression estimators in the linear regression models with non-spherical errors

The present paper considers a family of ordinary ridge regression estimators in the linear regression model when the disturbances covariance matrix depends upon a few unknown parameters. An asymptotic expansion for the distribution of the ridge regression estimator is developed and under the quadratic loss function its asymptotic risk is compared with that of the feasible GLS estimator.