# Search results

1. ### Sample size calculation

Totally agree! Phase 2/3 is type of seamless design in what we conduct interim analysis (in my example when 50% of total subjects are finished study), assess the primary endpoint and corresponding p-value, and according to fulitlity and efficacy boundaries, we may conclude to continued trial...
2. ### Sample size calculation

Hi everyone! Can anyone helps with calculation sample size for trial? We are planned 2/3 phase with group-sequential design (two stage) with re-estimation procedure for some rare disease (to prove superiority), expected succes rate in treatment group is around 85%, and 75% for control group...
3. ### Block randomization

In R you may do block randomization using blockrand function from blockrand package.
4. ### Block randomization

Hello everyone! Does anyone know packages or functions on R with which you can do block randomization with allocation ratio 3:1?
5. ### Sample size for observational study

Hi everyone! I should to calculate sample size for observational study in that the primary endpoint is to assess the distribution of COPD by 4 classess (COLD). According to article i know expected distribution by class: 1 class: 16% 2 class: 25% 3 class: 28% 4 class: 31% How I may to estimate...
6. ### Control the type 1 error

Hello, everyone! In my reasearch I have two primary endpoints - overall survival and progression-free survival. I test the superiority hypothesis H0: hazard ratio more than superiority margin and Ha is hazard ratio is less than superiority margin. And my question is: What method of control type...
7. ### Help with sample size for overall survival endpoint

Yes, no interim analysis, just a single primary analysis at 36 months after the last person is enrolled
8. ### Help with sample size for overall survival endpoint

Hi everyone! Please help to calculate sample size for primary endpoint - overall survival after 36 months. It is a superiority hypothesis: H0: ϒ ≥ δ and H1: ϒ < δ, where ϒ- hazard ratio, δ- superiority margin. Type I error: 2.5%, Type II error: 20% (β=0.2), expected hazard ratio for tested and...