Family scholarly culture and educational success: Books and schooling in 27 nations

Children growing up in homes with many books get 3 years more schooling than children from bookless homes, independent of their parents’ education, occupation, and class. This is as great an advantage as having university educated rather than unschooled parents, and twice the advantage of having a professional rather than an unskilled father. It holds equally in rich nations and in poor; in the past and in the present; under Communism, capitalism, and Apartheid; and most strongly in China. Data are from representative national samples in 27 nations, with over 70,000 cases, analyzed using multi-level linear and probit models with multiple imputation of missing data.     

Two separate effects of variance heterogeneity on the validity and power of significance tests of location

Heterogeneity of variances of treatment groups influences the validity and power of significance tests of location in two distinct ways. First, if sample sizes are unequal, the Type I error rate and power are depressed if a larger variance is associated with a larger sample size, and elevated if a larger variance is associated with a smaller sample size. This well-established effect, which occurs in t and F tests, and to a lesser degree in nonparametric rank tests, results from unequal contributions of pooled estimates of error variance in the computation of test statistics. It is observed in samples from normal distributions, as well as non-normal distributions of various shapes. Second, transformation of scores from skewed distributions with unequal variances to ranks produces differences in the means of the ranks assigned to the respective groups, even if the means of the initial groups are equal, and a subsequent inflation of Type I error rates and power. This effect occurs for all sample sizes, equal and unequal. For the t test, the discrepancy diminishes, and for the Wilcoxon–Mann–Whitney test, it becomes larger, as sample size increases. The Welch separate-variance t test overcomes the first effect but not the second. Because of interaction of these separate effects, the validity and power of both parametric and nonparametric tests performed on samples of any size from unknown distributions with possibly unequal variances can be distorted in unpredictable ways.     

SIMULATION FOR FIRE DEPARTMENT DEPLOYMENT POLICY ANALYSIS

This paper discusses the use of simulation in the determination and analysis of alternative deployment strategies for urban fire supression systems. The simulation model utilizes the New York City-Rand Institute simulator of fire department operations tailored for use with the Denver Fire department. A distinction is made between static deployment (where mathematical programming methods are used) and dynamic analysis (which employs the simulation model). The simulation model is described, as are its extensive data requirements. The results discuss measures of validation of the simulation and outline the recommendations resulting from this research.     

A DECISION MODEL FOR SELECTING ALTERNATIVE HYPOTHESES: AN EXTENSION*

A decision rule for selecting a one-sided or two-sided alternative for a standard hypothesis test is developed. Using a prior distribution of the parameter to be tested, the alternative is chosen which maximizes expected power. The test of a binomial parameter is presented to illustrate the method.     

犯罪作为社会控制

对于犯罪,人们通常关注的是它本身的违法性和社会危害性,但是在更广阔的历史和空间的角度上,犯罪其实是对先前侵犯行为的报复。众多的社会学调查的结果表明,不管在过去还是当下,刑法学中认为的犯罪行为人很多情况下都是受害人,而犯罪行为是他们对先前不满采取的自助行为,是对不轨行为的反应,因而犯罪成为一种社会控制。从理论上分析这一自助方式,可以预测和解释犯罪。     

LIQUIDITY CONSTRAINTS WITH ENDOGENOUS INCOME

This article examines liquidity constraints within the household's intertemporal model with nonseparable consumption and leisure. The model includes wage income in the minimum wealth constraint. We derive an estimable equation for employed households that holds whether or not the family is credit constrained. The formulation enables direct testing for liquidity constraints. Empirical findings using the Panel Study of Income Dynamics strongly support the existence of debt constraints. Credit constrained households have significantly lower levels of consumption, disposable income, saving, and wage rates, a higher average propensity to consume, and smaller labor hours for the spouse but not the head. ( JEL D91, J22)     

Public Policy and the Displacement Effects of Casinos: A Case Study of Riverboat Gambling in Missouri

A critical issue in assessing the economic impact of casinos is whether gambling activity displaces consumer expenditure from conventional retail establishments. We test this hypothesis using industry-level, time series data for eleven counties in Missouri, a state that recently introduced riverboats. Our results are generally inconsistent with the displacement hypothesis. However, we do find evidence of substitution between gambling and other businesses in the entertainment and amusement sector. This conclusion lends credence to the view that gaming serves as a substitute for other forms of entertainment. Our results also imply that the search for displacement should probably be focused on activities that constitute the closest consumer substitutes. We conclude with a discussion of the policy implications for state regulation of this new source of revenue.     

Sequential design approaches for bioequivalence studies with crossover designs

The planning of bioequivalence (BE) studies, as for any clinical trial, requires a priori specification of an effect size for the determination of power and an assumption about the variance. The specified effect size may be overly optimistic, leading to an underpowered study. The assumed variance can be either too small or too large, leading, respectively, to studies that are underpowered or overly large. There has been much work in the clinical trials field on various types of sequential designs that include sample size reestimation after the trial is started, but these have seen only little use in BE studies. The purpose of this work was to validate at least one such method for crossover design BE studies. Specifically, we considered sample size reestimation for a two-stage trial based on the variance estimated from the first stage. We identified two methods based on Pocock's method for group sequential trials that met our requirement for at most negligible increase in type I error rate.