We study use of a Scheffé-style simultaneous confidence band as applied to low-dose risk estimation with quantal response data. We consider two formulations for the dose-response risk function, an Abbott-adjusted Weibull model and an Abbott-adjusted log-logistic model. Using the simultaneous construction, we derive methods for estimating upper confidence limits on predicted extra risk and, by inverting the upper bands on risk, lower bounds on the benchmark dose, or BMD, at which a specific level of 'benchmark risk' is attained. Monte Carlo evaluations explore the operating characteristics of the simultaneous limits.

In modern environmental risk analysis, inferences are often desired on those low dose levels at which a fixed benchmark risk is achieved. In this paper, we study the use of confidence limits on parameters from a simple one-stage model of risk historically popular in benchmark analysis with quantal data. Based on these confidence bounds, we present methods for deriving upper confidence limits on extra risk and lower bounds on the benchmark dose. The methods are seen to extend automatically to the case where simultaneous inferences are desired at multiple doses. Monte Carlo evaluations explore characteristics of the parameter estimates and the confidence limits under this setting.

The distinction between alexithymia and coping in relation to posttraumatic stress has not been fully explored. The present study examined the extent to which alexithymia explained unique variance in posttraumatic stress, beyond the variance explained by coping, in a sample of trauma-exposed adults (N = 706; M age = 19.41 years, SD = 1.5; 77.1% female). Then, we explored the effect of race on these associations, comparing participants who identified as Black (n = 275) to those who identified as White (n = 337). Avoidant-emotional coping showed stronger correlations (compared with problem-focused and active-emotional coping) with total alexithymia, difficulty identifying feelings, and difficulty describing feelings. In regression analyses, we found alexithymia explained unique variance in posttraumatic stress severity beyond the effect of coping. Results did not differ by racial identity. These findings suggest that despite some overlap between alexithymia and coping, each shows unique relations with posttraumatic stress.

No abstract

Participants race across a university campus, completing challenging mathematical tasks that correspond to NCTM's Standards.