Bioequivalence and Bioavailability Forum

Dear Helmut,

❝ Confirmed. First I thought this might happen when the last datapoint is very low (close to the x-axis), but this is not the case. Sometimes I couldn't select a datapoint at ~50% of the y-axis; I don't see a clear pattern. Dataset upon request.

I will try to zoom out the plot next time by setting the lower limit of y-xis (conc.) to, for instance, minus (Cmax/10) (a negative value; 10 is just an arbitrary number here). Hopefully, the conc. near zero will display better. As the below message that I replied to D. Labes, you can try the trick.

❝ BTW: Why 2-4 points - not more?

In previous version, it was set to the exact 3 data points. I changed that to 2-4 data points. I remember that it's at least 3 data points based on FDA Guideline. Let me know if I am wrong. What is the max. number of data points required in manual selection?

❝ [cut here]

❝ results, I got:

❝ Error in pooledSD(object) :

❝   No degrees of freedom for estimating std. dev.

Were these data points very close to zero? I don't have such a situation before. Do you think the zoom-out approach as I mentioned above will be able to solve the problem?