Confusing [Regulatives / Guidelines]

posted by Helmut Homepage – Vienna, Austria, 2019-03-02 15:37 (527 d 22:01 ago) – Posting: # 19985
Views: 3,214

Hi John,

» Here is the exact wordings from the table (if that makes any difference to what I posted). Note that the summary table also presented +/- Westlake 95% CI..
»
» Cmax(n=24):
» Detectable differences(%)=13.28

“Detectable difference” stinks of the FDA’s 80/20 rule (at least 80% post hoc power to detect a 20% difference). Was applied till 1992. IMHO, since 13.28% < 20%, Cmax failed.

» T/R Ratio=93.86%
» +/- Westlake 95% CI=20.12%

Why 95%? However, Westlake’s CI is an information sink (example). By fiddling around with the t-values his CI is always symmetric around 100%. He suspected that clinicians are not comfortable with a CI which is asymmetric (see this post). As a side effect the T/R-ratio should not be given.

» One sided t-test 90% CI:Lower limit= -18.33%, Upper Limit= -6.36%

Here’s the other way ’round. Should be 95%.

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Helmut Schütz
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