A doubly censoring scheme occurs when the lifetimes T being measured,from a well-known time origin, are exactly observed within a window [L, R] of observational time and are otherwise censored either from above (right-censored observations)or below (left-censored observations). Sample data consists on the pairs (U, δ)where U = min{R, max{T, L}} and δ indicates whether T is exactly observed (δ =...

Small-study effects are a common threat in systematic reviews and may indicate publication bias. Their existence is often verified by visual inspection of the funnel plot. Formal tests to assess the presence of funnel plot asymmetry typically estimate the association between the reported effect size and their standard error, the total sample size, or the inverse of the total sample size. In thi...

When planning a randomized clinical trial, careful consideration must be given to how participants are selected for various arms of a study. Selection and accidental bias may occur when participants are not assigned to study groups with equal probability. A simple random allocation scheme is a process by which each participant has equal likelihood of being assigned to treatment versus referent ...

OBJECTIVE To identify predictive factors of urinary retention following a tension-free vaginal tape (TVT) procedure, so that patients may be better advised of their risk of undergoing catheterization and tape release. METHOD A retrospective review of women who underwent a TVT procedure over five years. Patient age, pressure flow rate, concomitant vaginal surgery, and the form of anesthesia us...

BACKGROUND Although some nonparametric methods have been proposed in the literature to test for the equality of median survival times for censored data in medical research, in general they have inflated type I error rates, which make their use limited in practice, especially when the sample sizes are small. METHODS In this paper, we propose a new nonparametric test with a simple test statisti...

Cancer clinical trials are important for resolving cancer health disparities for several reasons; however, clinical trial participation among African Americans is significantly lower than Caucasians. This study engaged focus groups of 82 female African American cancer survivors or cancer caregivers, including those in better resourced, more urban areas and less resourced, more rural areas. Info...

BACKGROUND Youth comprise 40% of the world's unemployed, a status associated with adverse wellbeing and social, health, and economic costs. This systematic review and meta-analysis review synthesises the literature on the effectiveness of interventions targeting young people not in employment, education, or training (NEET). METHODS Randomised and quasi-randomised trials with a concurrent or c...

The relationship between the two estimates of genetic variation at the DNA level, namely the number of segregating sites and the average number of nucleotide differences estimated from pairwise comparison, is investigated. It is found that the correlation between these two estimates is large when the sample size is small, and decreases slowly as the sample size increases. Using the relationship...

It is shown that in the case of heterogenous censoring distributions studentized survival tests can be carried out as conditional permutation tests given the order statistics and their censoring status. The result is based on a conditional central limit theorem for permutation statistics. It holds as well for linear test statistics as for sup-statistics. The procedure works under one of the fol...

Reliability demonstration tests require demonstrating, with some level of confidence, that reliability exceeds a given standard. Demonstration tests can be expensive and time-consuming. Careful planning of sample size and test length are essential. This paper develops exact theoretical methods, based on pivotal quantities and confidence intervals, to aid in proper sample size selection and dete...