## Exact (Owen’s Q) [Power / Sample Size]

Hi Imph,

Diletti (1981), which is exact based on Owen’s Q function. Julious is based on an approximation by the noncentral

Don’t. Chow’s is based on the shifted central

I suggest to estimate sample sizes with functions of the -package

Whilst in many cases sample sizes based on the shifted central

❝ […] which formula to choose to calculate the number of subjects among all the formulas published: Dilleti, Chow, Julious,...

Diletti (1981), which is exact based on Owen’s Q function. Julious is based on an approximation by the noncentral

*t*-distribution and fine as well.❝ For now I am using chow's formula, I would like to know if there is a plausible reference that supports its use.

Don’t. Chow’s is based on the shifted central

*t*-distribution and the paper contains typos. See also this post.I suggest to estimate sample sizes with functions of the -package

`PowerTOST`

. All three methods are implemented, where the exact one is the default.Whilst in many cases sample sizes based on the shifted central

*t*-distribution will be equal to the others, sometimes estimated sample sizes are*larger*than necessary. The background is shown in an article.—

Helmut Schütz

The quality of responses received is directly proportional to the quality of the question asked. 🚮

Science Quotes

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

The quality of responses received is directly proportional to the quality of the question asked. 🚮

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### Complete thread:

- Choosing formula for sample size Imph 2021-10-20 11:03 [Power / Sample Size]
- Exact (Owen’s Q)Helmut 2021-10-20 11:36
- Exact (Owen’s Q) Imph 2021-10-20 12:53
- Exact (Owen’s Q) Helmut 2021-10-20 13:26
- Exact (Owen’s Q) Imph 2021-10-24 10:41
- n iteratively from power Helmut 2021-10-24 10:54
- aproximate n d_labes 2021-10-24 19:26

- Exact (Owen’s Q) Willem Talloen 2022-09-01 15:48
- PowerTOST & FDA Helmut 2022-09-01 16:31

- Exact (Owen’s Q) Imph 2021-10-24 10:41

- Exact (Owen’s Q) Helmut 2021-10-20 13:26

- Exact (Owen’s Q) Imph 2021-10-20 12:53

- Exact (Owen’s Q)Helmut 2021-10-20 11:36