## Ratio calculation of fully replicate study [RSABE / ABEL]

Hi Mithu,

» » Without knowing your SAS code it would be reading tea leaves.
»
» We have used Progesterone program.

… which nowhere gives the subject’s T/R-ratios.

» » $$x/y=\exp (\log_{e}x-\log_{e}y)\;\left\{x,y \in \mathbb{R}^{+} \right\}\; {\color{red}{\neq}}\log_{e}x/\log_{e}y$$
» Still I could not understand.

Calculating the ratio of logs (2. of your OP) is nonsense.
The individual averaged log-differences $$I_{ij}$$ (for subject $$i$$ in sequence $$j$$) are computed in the FDA’s SAS macro by

ilat=0.5*(lat1t+lat2t-lat1r-lat2r);

Simply back-transform them.

Let’s have a look at the EMA’s full replicate reference data set:

SUBJECT   DATA  FORMULATION  PERIOD  SEQUENCE  logDATA     1    2285.96      R          1      BABA    7.734541    1    1955.82      T          2      BABA    7.578565    1    1345.94      R          3      BABA    7.204848    1    2856.24      T          4      BABA    7.957261

Then$$\overline{I_{11}}=0.5\times(7.578565+7.957261-7.734541-7.204848)=0.2982185$$and$$\overline{T_{11}/R_{11}}=\exp \overline{I_{11}}=\exp 0.2982185=1.347456$$Confirmed by Phoenix WinNonlin’s RSABE-template and my pocket calculator.

Which leaves my second question open:

» » Why on earth do you want to use Excel?

Dif-tor heh smusma 🖖
Helmut Schütz

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