We present a simple sample-size formula for weighted log-rank statistics applied to clustered survival data with variable cluster sizes and arbitrary treatment assignments within clusters. This ...

An advantage of the supremum log-rank over the standard log-rank statistic is an increased sensitivity to a wider variety of stochastic ordering alternatives. In this article, we develop a formula for ...

WASHINGTON - The poverty rate among older Americans could be nearly twice as high as the traditional 10 percent level, according to a revision of a half-century-old formula for calculating medical ...