Measuring agreement between two statistics with applications to age standardization

Summary.  We detail a general method for measuring agreement between two statistics. An application is two ratios of directly standardized rates which differ only by the choice of the standard. If the statistics have a high value for the coefficient of agreement then the expected squared difference between the statistics is small relative to the variance of the average of the two statistics, and inferences vary little by changing statistics. The estimation of a coefficient of agreement between two statistics is not straightforward because there is only one pair of observed values, each statistic calculated from the data. We introduce estimators of the coefficient of agreement for two statistics and discuss their use, especially as applied to functions of standardized rates.     

Statistical Distributions of Daily Breathing Rates for Narrow Age Groups of Infants and Children

Children may be more susceptible to toxicity from some environmental chemicals than adults. This susceptibility may occur during narrow age periods (windows), which can last from days to years depending on the toxicant. Breathing rates specific to narrow age periods are useful to assess inhalation dose during suspected windows of susceptibility. Because existing breathing rates used in risk assessment are typically for broad age ranges or are based on data not representative of the population, we derived daily breathing rates for narrow age ranges of children designed to be more representative of the current U.S. children's population. These rates were derived using the metabolic conversion method of Layton (1993) and energy intake data adjusted to represent the U.S. population from a relatively recent dietary survey (CSFII 1994–1996, 1998). We calculated conversion factors more specific to children than those previously used. Both nonnormalized (L/day) and normalized (L/kg-day) breathing rates were derived and found comparable to rates derived using energy estimates that are accurate for the individuals sampled but not representative of the population. Estimates of breathing rate variability within a population can be used with stochastic techniques to characterize the range of risk in the population from inhalation exposures. For each age and age-gender group, we present the mean, standard error of the mean, percentiles (50th, 90th, and 95th), geometric mean, standard deviation, 95th percentile, and best-fit parametric models of the breathing rate distributions. The standard errors characterize uncertainty in the parameter estimate, while the percentiles describe the combined interindividual and intra-individual variability of the sampled population. These breathing rates can be used for risk assessment of subchronic and chronic inhalation exposures of narrow age groups of children.     

Diagnostics for dependence within time series extremes

Summary. The analysis of extreme values within a stationary time series entails various assumptions concerning its long- and short-range dependence. We present a range of new diagnostic tools for assessing whether these assumptions are appropriate and for identifying structure within extreme events. These tools are based on tail characteristics of joint survivor functions but can be implemented by using existing estimation methods for extremes of univariate independent and identically distributed variables. Our diagnostic aids are illustrated through theoretical examples, simulation studies and by application to rainfall and exchange rate data. On the basis of these diagnostics we can explain characteristics that are found in the observed extreme events of these series and also gain insight into the properties of events that are more extreme than those observed.     

Deposit Insurance,Institutions, and Bank Interest Rates

Many recent institutional reforms of the financial system have relied on the introduction of an explicit scheme of deposit insurance. This instrument aims at two main targets, contributing to systemic stability and protecting depositors. However, it may also affect the interest rate spread in the banking system, which can be viewed as an indicator of either inefficiency or market power in this financial segment. This paper provides an empirical investigation of the effect of deposit insurance and other institutional and economic variables on bank interest rates across countries. We find that deposit insurance increases the lending–deposit spread in banking. The main effect seems to arise not from the deposit side though, but from an increase in the lending rate. We interpret this result as evidence of the presence of moral hazard problems related to this instrument. We also find that higher quality of institutions is associated with lower spreads, thus contributing to eroding sources of market power in the banking sector.     

Deconvolution with supersmooth distributions

Nonparametric deconvolution problems require one to recover an unknown density when the data are contaminated with errors. Optimal global rates of convergence are found under the weighted L_p-loss (1 ≤ p ≤ ∞). It appears that the optimal rates of convergence are extremely low for supersmooth error distributions. To resolve this difficulty, we examine how high the noise level can be for deconvolution to be feasible, and for the deconvolution estimate to be as good as the ordinary density estimate. It is shown that if the noise level is not too high, nonparametric Gaussian deconvolution can still be practical. Several simulation studies are also presented.     

Testing symmetry under a skew Laplace model

We develop tests of hypothesis about symmetry based on samples from possibly asymmetric Laplace distributions and present exact and limiting distribution of the test statistics. We postulate that the test statistic derived under the Laplace model is a rational choice as a measure of skewness and can be used in testing symmetry for other, quite general classes of skew distributions. Our results are applied to foreign exchange rates for 15 currencies.     

我国高校办学经费不足的原因及对策探讨

本文浅议在市场经济条件下,我国高等教育在蓬勃发展的同时,高等学校办学经费所面临的主要问题,并通过分析提出解决这些问题的办法。     

高校社会捐赠与构建和谐社会

社会利益结构是和谐社会构建的基础,高校社会捐赠属于公益捐赠,是捐赠者的一种经济社会行为。从分析社会利益结构的发展变化出发,运用经济社会学的基本原理,分析认为高校社会捐赠对于构建和谐社会具有重要意义,针对我国高校社会捐赠事业发展的现状,提出了对策和建议。     

基本养老保险覆盖面扩展决定因素实证研究

扩大基本养老保险覆盖面是我国社会保障制度改革的优先目标之一。本文通过对19982003年分省数据的实证分析,发现各省之间的基本养老保险覆盖面的差异,主要是由它们的经济发展水平和市场化程度这两个宏观经济因素与基本养老金给付标准和财政对社会保障补助支出这两个政策因素共同决定的。基于这些发现,考虑到我国经济持续发展和市场化改革深化的趋势,我们对我国社会保障事业的发展持谨慎乐观的态度,并认为在目前,“低水平、高覆盖”仍然是一个符合国情、必须坚持的合理政策选择,地方政府应当在财力许可的范围内,增加对社会保障事业的财政投入。