We derive an explicit form for power/sample size calculation based on these two tests. A number of simulation studies have been used to illustrate the efficiency of the tests for the case-cohort ...

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 ...

Statistical power and sample size are inextricably linked, with a positive correlation between power and sample size. An assortment of factors influences the power of a test including the sample size, ...

Finally, we will use JMP and G*Power (a free software download) to practice obtaining required sample sizes based on different effect sizes and desired levels of power. Becoming comfortable with ...

Given the unacceptable quality of the sample size calculation of COVID-19 trials, I strongly suggest that all research teams include a statistician or invite a statistician to evaluate the ...