Geometric means ± SD [🇷 for BE/BA]
Hi ElMaestro & Lizhao,
Between – yes. (m/V)2? Ahem…
I suggest to plot geometric means* ± backtransformed standard deviations. Concentrations likely follow a log-normal distribution. Arithmetic means ± SD can lead to bizarre plots (like this one published by the FDA, page 12 of the PDF).
❝ ❝ If I want to plot a mean plot (mean and error bars) of a crossover biequivalence study, should I use within-subject confidence intervals or between-subject confidence intervals?
❝
❝ I think you can plot those curves in any way you want? The BE decision is taken on basis of the CI's.
❝ If you plot Conc versus time and average across subjects then you would often choose to use between-subject variances for error bars.
Between – yes. (m/V)2? Ahem…
I suggest to plot geometric means* ± backtransformed standard deviations. Concentrations likely follow a log-normal distribution. Arithmetic means ± SD can lead to bizarre plots (like this one published by the FDA, page 12 of the PDF).
- Having subjects with BQLs leads to trouble. Can be handled in an SOP.
- Calculate the geometric mean if ≥⅔ of subjects at the given time point have concentrations ≥LLOQ and none otherwise, or
- only (!) for the mean plots replace BQLs with LLOQ/2.
- Calculate the geometric mean if ≥⅔ of subjects at the given time point have concentrations ≥LLOQ and none otherwise, or
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Dif-tor heh smusma 🖖🏼 Довге життя Україна!
![[image]](https://static.bebac.at/pics/Blue_and_yellow_ribbon_UA.png)
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Complete thread:
- R code for analyzing classical 2X2 crossover designed bioequivalence data lizhao 2016-01-22 00:13 [🇷 for BE/BA]
- R code for analyzing classical 2X2 crossover designed bioequivalence data ElMaestro 2016-01-22 00:59
- R code for analyzing classical 2X2 crossover designed bioequivalence data lizhao 2016-01-22 01:26
- On random effects and bogus statements ElMaestro 2016-01-22 12:13
- FDA 'own' SAS code for 2x2 d_labes 2016-01-27 09:57
- FDA 'own' SAS code for 2x2 nobody 2016-01-27 10:09
- OT: PM to ElMaestro Helmut 2016-01-27 13:39
- On coffee and such... ElMaestro 2016-01-27 13:47
- FDA 'own' SAS code for 2x2 nobody 2016-01-27 10:09
- Geometric means ± SDHelmut 2016-01-27 13:51
- Geometric means ± SD nobody 2016-01-27 15:20
- Money makes the world go ’round Helmut 2016-01-27 16:11
- Money makes the world go ’round nobody 2016-01-27 16:31
- Fixed or random effect kumarnaidu 2016-11-04 14:05
- PROC GLM fixes Subject mittyri 2016-11-04 23:00
- PROC GLM fixes Subject kumarnaidu 2016-11-05 05:22
- PROC GLM fixes Subject mittyri 2016-11-05 10:13
- PROC GLM fixes Subject kumarnaidu 2016-11-07 06:24
- PROC GLM fixes Subject mittyri 2016-11-07 11:57
- PROC GLM fixes Subject kumarnaidu 2016-11-07 12:42
- PROC GLM fixes Subject mittyri 2016-11-07 11:57
- PROC GLM fixes Subject kumarnaidu 2016-11-07 06:24
- PROC GLM fixes Subject mittyri 2016-11-05 10:13
- PROC GLM fixes Subject kumarnaidu 2016-11-05 05:22
- PROC GLM fixes Subject mittyri 2016-11-04 23:00
- Fixed or random effect kumarnaidu 2016-11-04 14:05
- Money makes the world go ’round nobody 2016-01-27 16:31
- Money makes the world go ’round Helmut 2016-01-27 16:11
- Geometric means ± SD Ben 2016-11-08 21:20
- Misunderstanding Helmut 2016-11-09 15:29
- Misunderstanding Ben 2016-11-14 19:40
- RTFM Helmut 2016-11-14 21:50
- Misunderstanding Ben 2016-11-14 19:40
- Misunderstanding Helmut 2016-11-09 15:29
- Geometric means ± SD nobody 2016-01-27 15:20
- FDA 'own' SAS code for 2x2 d_labes 2016-01-27 09:57
- On random effects and bogus statements ElMaestro 2016-01-22 12:13
- R code for analyzing classical 2X2 crossover designed bioequivalence data lizhao 2016-01-22 01:26
- R code for analyzing classical 2X2 crossover designed bioequivalence data ElMaestro 2016-01-22 00:59