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RegisterTransform or not transform [PK / PD]
Dear Helmut!
First many thanks for sharing this information.
Your pictures are a good example of the inherent difficulties in determining the distribution form empirical.
Thus I'm a fan of the arguments for the log-normal distribution via theoretical PK considerations (@EM: even if regulators have written down them in guidances
).
IMHO this is a good choice
.
Although the residuals (and these count at least I think) don't show a very distinct picture.
BTW: Since these metrics (the ones you have shown) are usually not primaries then the question of their (their residuals) distribution is not so much of concern I think. I would handle them only in a descriptive way (mean, sd, median and ... and ...). Or do you analyze those metrics also via ANOVA and (1-2*alpha) CI's in a standard fashion?
My originally question was more in the direction of swing metrics. Do you have similar data for PTF or swing? As for ratios of two terms deemed as log-normally distributed I at least questioning a log-normal distribution. On the other hand one may argue with your results for Cmax/AUC ...
Geary 1947, Biometrika
Normality is a myth; there never was, and never will be, a normal distribution.
First many thanks for sharing this information.
Your pictures are a good example of the inherent difficulties in determining the distribution form empirical.
Thus I'm a fan of the arguments for the log-normal distribution via theoretical PK considerations (@EM: even if regulators have written down them in guidances
). ❝ I used to analyze HVD, t75%, and MRT untransformed and Cmax/AUC logtransformed ...
IMHO this is a good choice
.Although the residuals (and these count at least I think) don't show a very distinct picture.
BTW: Since these metrics (the ones you have shown) are usually not primaries then the question of their (their residuals) distribution is not so much of concern I think. I would handle them only in a descriptive way (mean, sd, median and ... and ...). Or do you analyze those metrics also via ANOVA and (1-2*alpha) CI's in a standard fashion?
My originally question was more in the direction of swing metrics. Do you have similar data for PTF or swing? As for ratios of two terms deemed as log-normally distributed I at least questioning a log-normal distribution. On the other hand one may argue with your results for Cmax/AUC ...
Geary 1947, Biometrika
Normality is a myth; there never was, and never will be, a normal distribution.
—
Regards,
Detlew
Regards,
Detlew
Complete thread:
- Empiric distributions Helmut 2012-03-21 16:18 [PK / PD]
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- nitpicking ElMaestro 2012-03-21 17:32
- nitpicking Helmut 2012-03-22 16:06
- Empiric distributions martin 2012-03-21 21:16
- QQ-Plots Helmut 2012-03-22 01:17
- Transform or not transformd_labes 2012-03-22 09:31
- Transform or not transform Helmut 2012-03-22 13:27
- Transform or not transformd_labes 2012-03-22 09:31
- QQ-Plots Helmut 2012-03-22 01:17
- Empiric distributions ElMaestro 2012-03-22 18:16
- Empiric distributions Helmut 2012-03-23 01:50
- nitpicking ElMaestro 2012-03-21 17:32
Ing. Helmut Schütz