total (pooled) variance: examples [Power / Sample Size]

posted by BEQool  – 2023-05-04 10:17 (344 d 03:44 ago) – Posting: # 23542
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❝ Btw. total (pooled) CV in 2x2x2 can also be obtained by fitting the model with factors Formulations, Periods, Sequences (i.e. without Subjects(Sequences)). Then use MSE in equation:

CV=sqrt(e^(MSE)-1) (multiplicative model with residual variance sigma^2 which is estimated by MSE from ANOVA)

❝ For parallel design, it's trivial and only the total (pooled) CV can be obtained.


Interesting, thanks!

❝ For higher-order designs with more than two formulations I never tried it but it could be another option for recalculation.


Just for curiosity, with above mentioned data I tried some calculations for 3x6x3 design with and without factor Subject(Sequence) for both approaches (All at once and Two at a time) but I couldnt get matched CVtotal numbers so like you said there is probably another option for recalculation.

❝ ❝ ... it could happen with real-world data as well?

❝ Sometimes (not often) it happens. It was discussed e.g. in this thread.


Thanks!

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