Bioequivalence and Bioavailability Forum • “classical” GSD alpha's

“classical” GSD alpha's [Two-Stage / GS Designs]

posted by d_labes – Berlin, Germany, 2015-12-03 10:47 (3853 d 15:46 ago) – Posting: # 15692
Views: 18,804
(edited on 2015-12-03 16:19)

Dear Helmut, dear Ben!

Two-sided or not two-sided, that is the question!

library(ldbounds)

# two-sided, check via summary()

bds2.poc <- bounds(t=c(0.5,1), iuse=c(2,2), alpha=rep(0.025,2))

summary(bds2.poc)

2*(1-pnorm(bds2.poc$upper.bounds))

gives us:
[1] 0.03100573 0.02774015


# one-sided

bds1.poc <- bounds(t=c(0.5,1), iuse=2, alpha=0.05)

summary(bds1.poc)

1-pnorm(bds1.poc$upper.bounds)

gives us:
[1] 0.03100573 0.02972542
simsalabim Ben's preferred values.

I personally opt for two-sided :cool:

.

BTW: Lan/deMets spending function is Pocock like.
Nearer to original Pocock are the mean of the critical values. Try
2*(1-pnorm(rep(mean(bds2.poc$upper.bounds),2)))
simsalabim, Pocock's natural constant! Nearly.
(1-pnorm(rep(mean(bds1.poc$upper.bounds),2)))
hokus pokus fidibus, Ben's magical number!

—
Regards,

Detlew

Complete thread:

Adaptive TSD vs. “classical” GSD Helmut 2015-11-27 19:05
- Adaptive TSD vs. “classical” GSD ElMaestro 2015-11-27 19:54
- “classical” GSD - E[n] d_labes 2015-11-30 11:15
  - Apples are pears by comparing the weight Helmut 2015-12-01 16:35
    - Apples are pears by comparing the weight d_labes 2015-12-03 09:16
      - Apples are pears by comparing the weight Helmut 2015-12-03 13:10
        
        Oranges d_labes 2015-12-03 13:56
- Adaptive TSD vs. “classical” GSD Ben 2015-12-02 19:27
  - Adaptive TSD vs. “classical” GSD Helmut 2015-12-03 03:11
    - “classical” GSD alpha'sd_labes 2015-12-03 09:47
      - N sufficiently large‽ Helmut 2015-12-03 14:56
        
        An other one with 0.0304 d_labes 2015-12-03 16:15
        
        An other one with 0.0304 Helmut 2015-12-03 16:26
    - Adaptive TSD vs. “classical” GSD Ben 2016-01-10 12:43