## AND or OR, that’s the question [Power / Sample Size]

Hi Chris,

Oh dear,

In the ‘Two at a Time’ approach T1 and T2 are treated independently. Hence, you have two separate distributions. You see that also in the evaluation, where you obtain two residual variance estimates.

❝ After some thoughts, I am wondering if the sample size estimation only considers one comparison. I found an old following post regarding this topic.

Oh dear,

*that*one! Opening Pandora’s box. However, only relevant if one would assess the study with the ‘All at Once’ approach (*i.e.*, an ANOVA of pooled data). The jury left the courtroom 2½ years ago and hasn’t returned ever since…❝ If we are considering both T1=R and T2=R, perhaps, we need to look at the bivariate distribution of the two test statistics when looking at the power. And these should be correlated as well, which makes things complicated. I am maybe missing something and was wondering if you could enlighten me on this subject.

In the ‘Two at a Time’ approach T1 and T2 are treated independently. Hence, you have two separate distributions. You see that also in the evaluation, where you obtain two residual variance estimates.

—

Helmut Schütz

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*Dif-tor heh smusma*🖖🏼 Довге життя Україна!_{}Helmut Schütz

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### Complete thread:

- Sample size for 3-way crossover chrisk 2022-08-09 18:55 [Power / Sample Size]
- Sample size for 3-way crossover Helmut 2022-08-10 11:30
- Sample size for 3-way crossover chrisk 2022-08-10 15:24
- AND or OR, that’s the question Helmut 2022-08-10 15:58
- AND or OR, that’s the question chrisk 2022-08-10 17:46
- AND or OR, that’s the question Helmut 2022-08-10 20:59
- AND or OR, that’s the question chrisk 2022-08-10 22:00
- AND or OR, that’s the questionHelmut 2022-08-11 15:25
- AND or OR, that’s the question chrisk 2022-08-12 16:02
- The unknown ρ Helmut 2022-08-17 15:04

- AND or OR, that’s the question chrisk 2022-08-12 16:02

- AND or OR, that’s the questionHelmut 2022-08-11 15:25

- AND or OR, that’s the question chrisk 2022-08-10 22:00

- AND or OR, that’s the question Helmut 2022-08-10 20:59

- AND or OR, that’s the question chrisk 2022-08-10 17:46

- AND or OR, that’s the question Helmut 2022-08-10 15:58

- Sample size for 3-way crossover chrisk 2022-08-10 15:24

- Sample size for 3-way crossover Helmut 2022-08-10 11:30