Dear all,
Does anybody know how to calculate sample size in the following
situation with Stata?
H0: s1=s2 (survival at 2 years) H1: one side (logrank non paramentric
test for exponential data)
Size ratio =1
S1=77,5%, s2=83,125%
Alfa=5%
Beta=20%
Lost follow-up 10% per year
Accrual time =2 years
Total study time =4 years (2 enrollment+2 follow-up)
I would like to perform this analysis with Stata but the manual doesn't
describe it.
Could you help me please?
Thanks a lot
Paola
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