## Validation of FDA's RSABE on NTIDs [RSABE / ABEL]

Dear Helmut,
Hope you are well.

I am trying to manually calculate the upper 90% CL of sWT/sWR in US FDA's RSABE for NTIDs(Draft Guidance on Warfarin).

I use BEBAC's sample data (page 14 of the PPT from this site) to validate/verify my calculation steps.

It will be greatly appreciated if you can help me on the following questions:
1. I manually calculate the sWR and sWT in Excel sheet, they are 0.124392769, 0.055720909, respectively. Are my results EXACTELY right?

2. In your slides, you have present the upper 95% CL of sWT/sWR 0.68427 ≤2.5.
I have calculated
lower 95% CL of sWT/sWR = 0.293238292
upper 95% CL of sWT/sWR = 0.684266753 (this is nearly the same as your result)

As US FDA's Guidance on Warfarin required, the upper 90% CI should be used, I also calculate the following:
lower 90% CL of sWT/sWR = 0.322597242
upper 90% CL of sWT/sWR = 0.621992961

Are the above results right?

I use the function Finv(0.1,16,16) and Finv(0.9,16,16) for the calculation of 90% CL of sWT/sWR,
and Finv(0.05,16,16) and Finv(0.95,16,16) for the calculation of 95% CL of sWT/sWR. Do I use the right function?

2. Would you please guide (step by step) me how to calculate CVwr CVwt? As shown in your slides, they are CVWR 12.49%, CVWT 5.58%. Although these two values are not used in calculation of "upper 90% CL of sWT/sWR".

Thank you for your great sample dataset which provides us a valuable bridge for us to learn and discuss this sparely used procedure.