Highs and lows: Some properties of the extremes of a diffusion and applications in finance

Observations on security prices, currency exchange rates, interest rates, and other financial time series usually include not only an open and close, but also a high and low price for the period. For Brown‐ian motion and certain diffusion processes, the information on high and low prices is of considerable value, particularly for estimating volatility, correlations between processes, and in the pricing of look‐back and barrier options. For pricing more general derivatives, this information is useful to the extent that change in volatility is an important ingredient in the price. The author gives a simple geometric device for generating the extremes of Brownian motion, and geometric Brownian motion; he then uses these extremes in the estimation of the volatility of the processes and to study survivorship bias.     

A Super Contribution to Vocational Theory: Work Values

This article traces the influence of Donald E. Super in introducing the concept of work values into career development and vocational theory. It reviews the conceptualization, taxonomy, and assessment of work values. Research bearing on Super's “onion model,” representing his views on the relationship of work values to other variables in the affective domain, is also presented. Finally, an overview is given of the research evidence regarding any functional role that work values actually play in the career development of individuals.     

Optimal adaptive sequential designs for crossover bioequivalence studies

In prior works, this group demonstrated the feasibility of valid adaptive sequential designs for crossover bioequivalence studies. In this paper, we extend the prior work to optimize adaptive sequential designs over a range of geometric mean test/reference ratios (GMRs) of 70–143% within each of two ranges of intra‐subject coefficient of variation (10–30% and 30–55%). These designs also introduce a futility decision for stopping the study after the first stage if there is sufficiently low likelihood of meeting bioequivalence criteria if the second stage were completed, as well as an upper limit on total study size. The optimized designs exhibited substantially improved performance characteristics over our previous adaptive sequential designs. Even though the optimized designs avoided undue inflation of type I error and maintained power at 80%, their average sample sizes were similar to or less than those of conventional single stage designs. Copyright © 2015 John Wiley & Sons, Ltd.     

Effects of Minimum Wages on Youth Employment: the Importance of Accounting for Spatial Correlation

The relationship between minimum wage increases and youth employment is investigated using county-level data and spatial econometric techniques. Results that account for spatial correlation indicate that a 10% increase in the effective minimum wage is associated with a 3.2% decrease in youth employment, a result that is 28% higher than the corresponding estimate that does not control for spatial correlation. Thus, estimates that do not take into account spatial correlation may significantly underestimate the negative effect of the minimum wage on teenage employment. Improperly controlling for factors that vary systematically over space can lead to incorrect inferences and misinform policy.

Socioeconomic Status and Infant Mortality: Evidence from a Rural Agricultural State

Abstract

This research examines the nature and extent to which the tradtional inverse relationship between infant mortality and socioeconomic status holds true in Kansas for the years around 1950,1960, and 1970. A social-area ranking approach and correlation and regression analysis failed to show the significant inverse relationship reported by other researchers. Contrary to expectations, a blurring and narrowing of this relationship resulted over the three time periods. A significant negative correlation resulted between the percentage of rural farm residents in counties and infant mortality, indicating that the social organization characteristics of a rural state may provide a quality of life that transcends traditional socioeconomic differentials.     

Exact and approximate distributions of the chi-square statistic for equiprobability

The distribution of the chi-square goodness-of-fit statistic is studied in the equiprobable case. Tables of exact critical values are given for a = .1, .05, .01, .005; k = 2(1)4, N = 26(1)50; k = 5, N = 26(1)40; k = 6(1)10, N = 26(1)30, where a is the desired significance level, k is the number of cells and N is the sample size. Methods of fitting the true distribution are compared. If k> 3, it is found that a simple additive adjustment to the asymptotic chi-square fit leads to high accuracy even for N between 10 and 20. For k = 2, the Yates corrected chi-square statistic is very accurately fitted by the usual chi-square distribution.     

Reports of childhood sexual abuse by adolescents and young adults: Stability over time

The consistency of childhood sexual abuse (CSA) reporting was explored in this study. Two‐hundred seventeen adolescents and young adults (ages 14–24) enrolled in urban health care clinics completed self‐report questionnaires assessing CSA and other problem behaviors at enrollment and at 7 months. Results indicated that the stability of CSA self‐report at two time points was poor (58% consistent nonreporters of CSA, 20% consistent reporters, 22% inconsistent reporters). Consistent and inconsistent reporters were differentiated on risk measures. Adolescents who endorsed more items from the CSA scale were five times more likely to be consistent reporters. In sum, adolescent CSA reporting was quite inconsistent over time. Using multi‐item scales and assessing CSA at two time points enhances accuracy of reporting.