Contributions to two-sample statistics

When testing the equality of the means from two independent normally distributed populations given that the variances of the two populations are unknown but assumed equal, the classical Student's two-sample t-test is recommended. If the underlying population distributions are normal with unequal and unknown variances, either Welch's t-statistic or Satterthwaite's approximate F test is suggested. However, Welch's procedure is non-robust under most non-normal distributions. There is a variable tolerance level around the strict assumptions of data independence, homogeneity of variances, and identical and normal distributions. Few textbooks offer alternatives when one or more of the underlying assumptions are not defensible. While there are more than a few non-parametric (rank) procedures that provide alternatives to Student's t-test, we restrict this review to the promising alternatives to Student's two-sample t-test in non-normal models.     

How right-to-work laws affect wages

I examine the wage effects of Right-To-Work (RTW). Using state-level data, I estimate that, ceteris paribus, RTW states have average wages that are significantly higher than non-RTW states. This result is robust is across a wide variety of specifications. An important distinctive of this study is that it controls for state economic conditions at the time states adopted RTW. States that adopted RTW were generally poorer than other states. Failure to control for these initial conditions may be the reason that previous studies have not identified a positive wage impact for RTW. I thank Kevin Grier for valuable comments and Lawrence Mishel of the Economie Policy Institute for constructive criticisms on an earlier version of this research.     

Drinking plans and drinking outcomes: examining young adults' weekend drinking behavior

This study examined relationships among drinking intentions, environments, and outcomes in a random sample of 566 undergraduate college students. Telephone interviews were conducted with respondents before and after a single weekend assessing drinking intentions for the coming weekend related to subsequent drinking behaviors. Latent class analyses found evidence for four distinct drinking environments distinguished by private/public setting and presence of few/many intoxicated people. There was evidence that the drinking environment mediated the relationship between drinking intentions and heavy episodic drinking in this young adult sample. Future research might focus on examining person/environment interactions as they relate to heavy episodic drinking.     

Risk, uncertainty and family formation: The social context of poverty groups

Abstract Despite the assumptions of many demographers that the net returns from children for non-elite groups in underdeveloped areas are likely to be negative, high fertility persists in most of these societies. Both cultural and institutional explanations have been proposed to account for this. We attempt to provide some mediation between these competing models, by introducing the elements of risk and uncertainty as factors likely to induce poverty and lead works to opt for the 'high fertility, low quality' pattern of investment of time and money in family formation. Drawing upon the work of Wharton in subsistence agriculture practices, several alternative decision-making models are proposed to account for both the persistence of high fertility, and the declines that have been registered in selected areas, such as Taiwan and perhaps China. The empirical work of Mueller on Taiwanese expectations of returns on children and the concomitant variation in family-size preferences is consistent with the models proposed. Some implications for uncertainty and risk-reduction strategies in family planning and other social welfare programmes are drawn.     

The impact of avian influenza on the Korean egg market: Who benefited?

The historical decomposition and directed acyclic graph methods are employed to estimate the effect of avian influenza in Korea on egg price transmission between the farm, wholesale, and retail levels. Our findings suggest that farm and retail egg prices are connected by the wholesale price. We also find that the farm-wholesale and the wholesale-retail margins increase during the avian influenza period. Our results imply that the retailer and wholesaler use their market power to increase their price during the food safety crisis. Therefore, the Korean government should control market power by allowing more emergency egg imports.     

Brownian–Laplace Motion and Its Use in Financial Modelling

Brownian-Laplace motion is a Lévy process which has both continuous (Brownian) and discontinuous (Laplace motion) components. The increments of the process follow a generalized normal Laplace (GNL) distribution which exhibits positive kurtosis and can be either symmetrical or exhibit skewness. The degree of kurtosis in the increments increases as the time between observations decreases. This and other properties render Brownian-Laplace motion a good candidate model for the motion of logarithmic stock prices. An option pricing formula for European call options is derived and it is used to calculate numerically the value of such an option both using nominal parameter values (to explore its dependence upon them) and those obtained as estimates from real stock price data.     

清教文化的性别形而上学： 对萨勒姆审巫案的诠释性解释

本文参照行动的文化结构化理论来解释北美历史上最大规模的猎巫事件--萨勒姆审巫案。对该案如何以及何以发生的理解与解释,需要考虑当时活跃在清教徒生活中复杂且被深刻感知的意义。本文揭示了清教文化中的危机。这场造成19个英国男女被绞死的审巫案是在原告、牧师及法官的主导下进行的,他们深植于一个充满意义的世界观中,操纵这一世界观,并最终借助合法暴力捍卫这一世界观。这个世界观是根据如下的紧张与矛盾节点而得以重建的：妇女在社会中的地位、殖民地与上帝之间的关系、世界如何运转的形而上信仰（如巫术与驱魂）。研究萨勒姆审巫案牵涉文化、诠释以及社会学解释的问题。为了回答这些问题,本文指出:（1）文化社会学的解释包含且不限于叙事性意向、意识、言说的意义及行动者的策略;（2）文化社会学的解释应把符号结构与政治经济学的互相嵌入纳入考虑范畴,但又注意不将前者化约为后者;（3）一个危机或事件的走势与参与其中的人们对危机的诠释之间相互纠缠。这意味着,文化社会学能够给出对社会生活的一种因果性诠释,从而超越在理解与解释之间长久存在的区分。