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RegisterExact (Owen’s Q) [Power / Sample Size]
posted by Helmut 
– Vienna, Austria, 2021-10-20 11:36 (214 d 10:22 ago) – Posting: # 22644
Views: 1,146
Hi Imph,
» […] 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![[image]](img/uploaded/Rlogo_15_12.svg)
-package
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.
» […] 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.
—
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Helmut Schütz
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Dif-tor heh smusma 🖖
Helmut Schütz
The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes
Complete thread:
- Choosing formula for sample size Imph 2021-10-20 11:03 [Power / Sample Size]
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- 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) 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
Ing. Helmut Schütz