## Hel­mert trans­for­ma­tion? [Software]

Hi Shatha,

❝ I have 2 treatments, 2 periods, crossover, multiple dose, steady state study.

❝ The last 3 pre-dose concentrations should be used for steady state verification for each subject in each period.

You can’t verify anything in science.
In statistics you can only try reject a properly stated null hypothesis – which is in your case what? Any test at level $$\small{\alpha}$$ has an unavoidable false positive rate. Do you want to exclude $$\small{(100\times\alpha)\%}$$ of subjects although they are in (pseu­do) steady state?

❝ I need your help to perform this verification using Helmert transformation method …

Do you have a reference demonstrating its application in PK? Never came across this approach in 40+ years. See there why statistical tests are nonsense – essentially because we don’t have a proper null.

Dif-tor heh smusma 🖖🏼 Довге життя Україна!
Helmut Schütz

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