Bioequivalence and Bioavailability Forum

Hi DShah,

❝ Still struggling with installation of R in organization …

It’t high time for your organization to learn that you need the right tools to perform your job.

I suppose it is tempting, if the only tool you have is a hammer,
to treat everything as if it were a nail.  Abraham H. Maslow (Toward a Psychology of Being, 1962)

❝ … and because of that I had asked for Sample size for NTI- FDA method in excel.

You would need to simulate 100,000 studies in each iteration (cause you will not hit the target with a lucky punch). I don’t say that’s impossible in Excel. But why the hell would one do that, if PowerTOST can give you the result in less than a second?

library(PowerTOST)
system.time(sampleN.NTIDFDA(CV = 0.1)) # use the defaults

+++++++++++ FDA method for NTIDs ++++++++++++
           Sample size estimation
---------------------------------------------
Study design:  2x2x4 (TRTR|RTRT)
log-transformed data (multiplicative model)
1e+05 studies for each step simulated.

alpha  = 0.05, target power = 0.8
CVw(T) = 0.1, CVw(R) = 0.1
True ratio     = 0.975
ABE limits     = 0.8 ... 1.25
Implied scABEL = 0.8000 ... 1.2500
Regulatory settings: FDA
- Regulatory const. = 1.053605
- 'CVcap'           = 0.2142

Sample size search
 n     power
14   0.717480
16   0.788690
18   0.841790

   user  system elapsed
   0.15    0.07    0.22