Bioequivalence and Bioavailability Forum

SAS and R (?) for variability comparison (FDA NTID Guidance) [General Sta­tis­tics]

posted by jag009  – NJ, 2015-09-26 00:42 (3920 d 09:04 ago) – Posting: # 15473
Views: 32,655

Hi,

❝ 4. Since FDA request that only subject who complete all 4 periods should be included in the analysis, for obtaining F-distribution value, it seems the degree of freedom v_T and v_R will always be equal, which is always Ntotal - 2 for full replicate. Right?

Where did you see this? I don't see it in the guidance. However, if you use FDA's SAS code (ie: Progesterone) to extract the variances etc etc, you WILL see that the code only takes subjects who completed both periods for Test and Ref. Example, any subjects who finished only 1T out of 2Ts will be dropped.

Take a look at previous threads involving the Concerta guidance (I started that thread and a few joined in. Sorry I don't have time to set the link now. Need to go party).

Lastly, as to why you get reverse upper and lower limit with the interval, I will try and goof around in SAS next week and see.

John

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Edit: The threads John mentioned above: #13991, #14150. [Helmut]

Complete thread:

• SAS and R (?) for variability comparison (FDA NTID Guidance) Shuanghe 2015-09-25 18:48 
  • SAS and R (?) for variability comparison (FDA NTID Guidance)jag009 2015-09-25 22:42
    • SAS and R (?) for variability comparison (FDA NTID Guidance) Shuanghe 2015-09-28 17:05
      • Missings d_labes 2015-09-30 10:52
        • Missings Shuanghe 2015-09-30 15:34
  • LaTeX, MathML, PNGs Helmut 2015-09-27 14:23
    • OT: LaTeX, MathML, PNGs Shuanghe 2015-09-28 17:32
      • OT: LaTeX, MathML, PNGs Helmut 2015-09-28 17:46
  • Quantiles of the F-distribution d_labes 2015-09-28 09:45
    • Quantiles of the F-distribution Shuanghe 2015-09-28 17:39
  • What's wrong with this picture? Shuanghe 2015-09-28 18:57
    • Suggestion Helmut 2015-09-29 02:22
      • Suggestion Shuanghe 2015-09-29 18:44
        • OT: The Hadleyverse d_labes 2015-09-30 08:44
    • Another suggestion for a R-solution d_labes 2015-09-29 14:26
      • Wow – another gem from the master! Helmut 2015-09-29 16:31
      • Another suggestion for a R-solution Shuanghe 2015-09-29 18:37
        • Another R-solution d_labes 2015-09-29 21:55
      • @Shuanghe: Outdated URL gvk 2019-05-21 11:36
  • SAS and R (?) for variability comparison (FDA NTID Guidance) M.tareq 2017-04-14 15:04
    • SAS and R (?) for variability comparison (FDA NTID Guidance) M.tareq 2017-04-15 01:01