Rank Tests for Matched Survival Data

In a clinical trial with the time to an event as the outcome of interest, we may randomize a number of matched subjects, such as litters, to different treatments. The number of treatments equals the number of subjects per litter, two in the case of twins. In this case, the survival times of matched subjects could be dependent. Although the standard rank tests, such as the logrank and Wilcoxon tests, for independent samples may be used to test the equality of marginal survival distributions, their standard error should be modified to accommodate the possible dependence of survival times between matched subjects. In this paper we propose a method of calculating the standard error of the rank tests for paired two-sample survival data. The method is naturally extended to that for K-sample tests under dependence.     

An efficient curve in stochastic capacity expansion

An optimum expansion of a single capacity is considered when the installation cost is very large and future demand is given by an evolving process of Wiener. Risk of expansion is evaluated and included in the decision criteria which links the capacity expansion problem with financial investment theory, Numerical results show the existence of an optimum expansion capacity and an efficient curve which represent the optimum choices with respect to the possible combinations of expansion cost and risk.     

A new random permutation test in ANOVA models

This paper developed an exact method of random permutations when testing both interaction and main effects in the two-way ANOVA model. The method of this paper can be regarded as a much improved model when compared with those of the previous studies such as Still and White (1981) and ter Braak (1992). We further conducted a simulation experiment in order to check the statistical performance of the proposed method. The proposed method works relatively well for small sample sizes compare with the existing methods. This work was supported by Korea Science and Engineering Foundation Grant (R14-2003-002-0100)     

Where angels fear to tread: Richard Schoenherr (1935–1996)

Richard Schoenherr, professor of sociology at the University of Wisconsin — Madison, passed away unexpectedly on 9 January 1996. He is memorialized in this essay for his scholarly contributions in the areas of teaching, research, and service.     

Censored Kullback-Leibler Information and Goodness-of-Fit Test with Type II Censored Data

The Kulback-Leibler information has been considered for establishing goodness-of-fit test statistics, which have been shown to perform very well (Arizono & Ohta, 1989; Ebrahimi et al., 1992, etc). In this paper, we propose censored Kullback-Leibler information to generalize the discussion of the Kullback-Leibler information to the censored case. Then we establish a goodness-of-fit test statistic based on the censored Kullback-Leibler information with the type 2 censored data, and compare the test statistics with some existing test statistics for the exponential and normal distributions.     

Gender in Academic Career Tracks: The Case of Korean Biochemists

How important is academic performance in obtaining a tenure‐track position in academic science? I use data on Korean biochemists and analyze them from both institutionalist and gender perspectives. In so doing, I illustrate the ways academic performance and gender interact with one another to maintain a gender barrier for Ph.D.s entering an academic career. The main findings are as follows. First, academic productivity did influence the job market outcomes, but the male scientists benefited from publications in both SCI and non‐SCI journals, whereas the female scientists benefited only from those in SCI journals. I also found a positive effect of overseas doctoral training only for the female scientists. Such analysis suggests that women as a minority in academic science are pressured to prove their legitimacy through more rigorous criteria of academic performance. Thus, ostensibly gender‐neutral rules of academic performance can be applied in such a way as to maintain gender inequality.     

Testing lack of symmetry in spatial–temporal processes

Symmetry and separability of a covariance function are common assumptions to simplify the modeling effort of spatial–temporal processes. However, many studies in environmental sciences show that real data have complex spatial–temporal dependency structures resulting from lack of symmetry or violation of other standard assumptions of the covariance function. In this study, we propose new formal tests for lack of symmetry by using spectral representations of the spatial–temporal covariance functions of regularly spaced spatial–temporal data. The advantage of the proposed tests is that classical analysis of variance (ANOVA) models can be used for detecting lack of symmetry inherent in spatial–temporal processes. We evaluate the performance of the tests with simulation studies and we apply them to air pollution data.     

NEGOTIATING CONTINUITY: Family and Religious Socialization for Second-Generation Asian Americans

This article examines second-generation Asian Americans' explanations of the significant influences on their own religious identities. Data include interviews (N = 73) with college-aged Asian Americans from different religious traditions and ethnic backgrounds. Respondents viewed families as the most significant influence on current religiosity. Mothers and fathers were mentioned most often, followed by extended kin, siblings, and relatives, who acted as what we call "reinforcers,""substitutes," or "contrasts" to the roles that parents played in religious socialization. These roles occurred along two religious configurations within families: heterogeneous or homogeneous degrees of religious commitment and religious affiliation. Directions for future research and contributions to the religious transmission literature follow.     

Technical Note – Pricing Below Cost Under Exchange‐Rate Risk

Pricing below cost is often classified as “dumping” in international trade and as “predatory pricing” in local markets. It is legally prohibited from practice because of earlier findings that it leads to predatory behavior by either eliminating competition or stealing market share. This study shows that a stochastic exchange rate can create incentives for a profit‐minded monopoly firm to set price below marginal cost. Our result departs from earlier findings because the optimal pricing decision is based on a rational behavior that does not exhibit any malicious intent against the competition to be considered as violating anti‐trust laws. The finding is a robust result, because our analysis demonstrates that this behavior occurs under various settings such as when the firm (i) is risk‐averse, (ii) can postpone prices until after exchange rates are realized, (iii) is capable of manufacturing in multiple countries, and (iv) operates under demand uncertainty in addition to the random exchange rate.