Bioequivalence and Bioavailability Forum 03:06 CEST

Main page Policy/Terms of Use Abbreviations Latest Posts

 Log in |  Register |  Search

BE parallel design [General Sta­tis­tics]

posted by Jaime_R - Barcelona, 2007-04-03 20:29  - Posting: # 621
Views: 10,575

Dear PKPDPKPD!

» I am a beginner PKPDPKPD and am trying to understand the procedure which is normally done by the software.

That's the best start of possible ones! ;-)

Never trust in any piece of software you haven't written yourself (and even then you should be cautious…)


» Just few questions to your instructions:
» 1. delta: should it be a difference of the raw data and log transformed data

After you have log-transformed the data, you are only working with these (in my example the Ys and not the Xs)

» 2. why shoudl i calculate the difference not ratio

Since we are now in the log-domain, we have transformed the multiplicative model (which would call for ratios!) into an additive model (therefore we are interested in differences of logs).
May be sound confusing, but once you have applied the transformation, all the nice examples given in statistical textbooks (99% are based on differences!) are working now…

Actually you can boil it down into three steps:
  1. Take logs of individual data (now you have a new data set)
  2. Apply common statistical methods (t-test, ANOVA, GLM, whatsoever,…)
  3. Antilog you results (point estimate, confidence limits)

Regards, Jaime

Complete thread:

Back to the forum Activity
 Mix view
Bioequivalence and Bioavailability Forum |  Admin contact
18,700 posts in 3,984 threads, 1,240 registered users;
online 17 (0 registered, 17 guests [including 13 identified bots]).

I suppose it is tempting, if the only tool you have is a hammer,
to treat everything as if it were a nail.    Abraham Maslow

The BIOEQUIVALENCE / BIOAVAILABILITY FORUM is hosted by
BEBAC Ing. Helmut Schütz
HTML5 RSS Feed