Sample Size for Survival Analysis


Menu location: Analysis_Sample Size_Survival Times.


This function gives you the minimum number of subjects that you require to detect a true ratio of median survival times (hr) with power POWER and two sided type I error probability ALPHA (Dupont, 1990; Schoenfeld and Richter, 1982).


The method used here is suitable for calculating sample sizes for studies that will be analysed by the log-rank test.


Information required


Practical issues


Technical validation

The estimated sample size per group n is calculated as:

- where α = alpha, β = 1 - power and zp is the standard normal deviate for probability p. n is rounded up to the closest integer. (1+1/m)/p is equivalent to 2/p in the first equation if the experimental and control group sizes are unequal.



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