Bioequivalence and Bioavailability Forum

❝ I got a problem related to the CV% (from a parallel BE) and confidence interval. The CV% from winnonlin is ~14% but confidence interval is 74%-136%. Although the sample size for this trial is rather small (19 for analysis), the calculated CV% using confidence interval in PowerTOST is quite large (~39%). I'm not sure why the result is counterintuitive.

library(PowerTOST)
cat(paste0("CV (total) ~",
    signif(100 * CI2CV(lower = 0.74, upper = 1.36,
                        n = 19, design = "parallel"), 2), "%\n"))

Unbalanced parallel design. n(i)= 10/9 assumed.
CV (total) ~39%

❝ Anyone have ideas?