Multiple Comparisons Among Mean Vectors When the Dimension is Larger Than the Total Sample Size

We consider pairwise multiple comparisons and multiple comparisons with a control among mean vectors for high-dimensional data under the multivariate normality. For such cases, the statistics based on the Dempster trace criterion are given, and also their approximate upper percentiles are derived by using the Bonferroni’s inequality. Finally, the accuracy of their approximate values is evaluated by Monte Carlo simulation.     

Asymptotic Inference for Performance Fees and the Predictability of Asset Returns

In this article, we provide analytical, simulation, and empirical evidence on a test of equal economic value from competing predictive models of asset returns. We define economic value using the concept of a performance fee—the amount an investor would be willing to pay to have access to an alternative predictive model used to make investment decisions. We establish that this fee can be asymptotically normal under modest assumptions. Monte Carlo evidence shows that our test can be accurately sized in reasonably large samples. We apply the proposed test to predictions of the U.S. equity premium.     

Applying statistical tests to empirically compare tabu search parameters for MAX 3-SATISFIABILITY: A case study

The application of stochastic heuristic, like tabu search or simulated annealing, to address hard discrete optimization problems has been an important advance for efficiently obtaining good solutions in a reasonable amount of computing time. A challenge when applying such heuristics is assessing when a particular set of parameter values yields better performance compared to other such sets of parameter values. For example, it can be difficult to determine the optimal mix of memory types to incorporate into tabu search. This in turn prompts users to undertake a trial and error phase to determine the best combination of parameter settings for the problem under study. Moreover, for a given problem instance, one set of heuristic parameter settings may yield a better solution than another set of parameters, for a given initial solution. However, the performance of this heuristic on this instance for a single heuristic execution is not sufficient to assert that the first set of parameter settings will always produce superior results than the second set of parameters, for all initial solutions.     

从奥康纳人物塑造看其狂欢化的怪诞风格

弗兰纳里.奥康纳作品的怪诞风格引人瞩目。从巴赫金的狂欢化理论来看,奥康纳人物塑造的狂欢化表现在同貌者、讽刺性摹拟型同貌相似者和正反同体的怪诞人物三个方面。奥康纳的怪诞风格并非阴森可怖,而是具有启发与变革的狂欢性。     

A fiducial approach to multiple comparisons

Comparing treatment means from populations that follow independent normal distributions is a common statistical problem. Many frequentist solutions exist to test for significant differences amongst the treatment means. A different approach would be to determine how likely it is that particular means are grouped as equal. We developed a fiducial framework for this situation. Our method provides fiducial probabilities that any number of means are equal based on the data and the assumed normal distributions. This methodology was developed when there is constant and non-constant variance across populations. Simulations suggest that our method selects the correct grouping of means at a relatively high rate for small sample sizes and asymptotic calculations demonstrate good properties. Additionally, we have demonstrated the flexibility in the methods ability to calculate the fiducial probability for any number of equal means. This was done by analyzing a simulated data set and a data set measuring the nitrogen levels of red clover plants that were inoculated with different treatments.     

Changes in the Satisfaction of Cohabitors Relative to Spouses Over Time

Family scholars have noted a gap in the subjective well‐being of cohabitors relative to spouses and have hypothesized that the size of this “cohabitation gap” varies depending on how far cohabitation has diffused in a society. For the first time we test this hypothesis across time in a single country, Italy, by analyzing 20 cross‐sectional, nationally representative surveys collected from 1993 to 2013 by the Italian Institute of Statistics (N = 279,190 partnered young adults). We find that differences in the assessments of family satisfaction between cohabitors and spouses have eroded over the years and that there has been no detectable cohabitation gap since 2011. In addition, we illustrate that the weakening of the cohabitation gap is attributable to the diffusion of cohabiting unions in Italian society.     

Commissioned analysis of surgical performance using routine data: lessons from the Bristol inquiry

The public inquiry into paediatric cardiac surgery at the Bristol Royal Infirmary commissioned the authors to design and conduct analyses of routine data sources to compare surgical outcomes between centres. Such analyses are necessarily complex in this context but were further hampered by the inherent inconsistencies and mediocre quality of the various sources of data. Three levels of analysis of increasing sophistication were carried out. The reasonable consistency of the results arising from different sources of data, together with a number of sensitivity analyses, led us to conclude that there had been excess mortality in Bristol in open heart operations on children under 1 year of age. We consider criticisms of our analysis and discuss the role of statisticians in this inquiry and their contribution to the final report of the inquiry. The potential statistical role in future programmes for monitoring clinical performance is highlighted.     

The Equivalence of Two Proportions Revisited

The classic conditional test for checking that the difference between two independent proportions is not null may not be appropriate in many circumstances. Dunnett & Gent (1977) showed that in clinical trials, in studies of drugs, etc, the aim is to prove the practical equality (equivalence) of both proportions. On other occasions the aim may be the opposite: i.e. to prove that the two proportions are substantially different (biologically significant). Both cases are usually solved by two one-sided tests (TOST test). In this article, this procedure is shown to be conservative and two true two-sided tests for each case are proposed.     

Educational differences in parents’ time with children: Cross‐national variations

We analyze time diary data from 24,546 married mothers and married fathers in Canada, Germany, Italy, and Norway to determine whether the effect of education on child‐care time varies cross‐nationally. Our results indicate that more educated mothers spend more time with children than less educated mothers in each country, despite substantial cross‐national variation in levels of economic support and services for families. This suggests that better educated mothers may have different parental values and behaviors than less educated mothers. Among fathers, however, education has no effect on child‐care time in Norway, and only weak effects in Germany. This suggests that family policies that provide economic support to families may reduce time constraints on fathers, thus ameliorating educational effects.