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 ...

Learn what residual standard deviation is, how to calculate it in regression analysis, and why it's crucial for measuring predictability and goodness-of-fit in data modeling.

An improved approximate formula is derived for determination of the sample sizes required for detecting the difference between two binomial parameters with specified type I and type II errors. Journal ...