for the moment unable to find "full alpha", only

https://gpaux.github.io/Mediana/CaseStudy04.html

The PFS analysis will be performed first at α = 0.025 (one-sided), followed by the OS analysis at the same level if a significant effect on PFS is established.

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For a two-tailed 95% confidence interval, the alpha value is 0.025, and the corresponding critical value is 1.96. This means that to calculate the upper and lower bounds of the confidence interval, we can take the mean ±1.96 standard deviations from the mean

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Note added at   2 godz. (2024-01-07 16:18:59 GMT)
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"one-sided alpha"

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"full alpha level"

https://www.bassconference.org/tutorials/BASS 2015 Huque Mus...

Should the secondary endpoint family be always analyzed at the full alpha level (e.g., at 0.05) after the trial is successful on one or more specified primary ...
132 pages

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What’s the Alpha Level? | Statistics

In frequentist statistics, the alpha level (also known as the significance level) is the probability of rejecting the null hypothesis when it is true. In the context of physiotherapy research, the null hypothesis might be that there is no difference in pain reduction between two different physiotherapy interventions. The alpha level is typically set at 0.05, which means that there is a 5% chance of incorrectly rejecting the null hypothesis (i.e., concluding that there is a difference in pain reduction when there actually isn’t) in the long term.

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https://context.reverso.net/translation/english-russian/sign...

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https://wiki.loginom.ru/articles/significance-level.html

https://www.quantics.co.uk/blog/multiplicity-what-is-it-and-...
Fallback method: An ordering of testing the hypotheses is pre-specified. The first hypothesis is tested at a level lower than the alpha level. If successful, the second hypothesis is tested at the full alpha level. If unsuccessful, the second hypothesis is tested at the difference of alpha and the first testing level.

https://new.nmicr.ru/wp-content/uploads/2022/09/abstracts_ro...
В нашем случае уточненный уровень значимости
равнялся p ≤ 0,025 (а не p ≤ 0,05).

https://keystatsolutions.com/documents/gost_r_iso_14155-2022...
Если проверяется гипотеза, то уровень значимости альфа 0,05 (двусторонний) и 0,025 (односторонний) и
степени между 0,8 и 1 минус альфа не нуждаются в обосновании. В зависимости от характеристик исследуемого
медицинского изделия или клинического исследования могут использоваться более высокие или более низкие
уровни значимости.

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https://cardiab.biomedcentral.com/articles/10.1186/s12933-01...
After having shown superiority for one of these endpoints, the used alpha can be shuffled to the other test: If H0(Sup2) is rejected at the alpha-level of ×0.8 alpha, then H0(Sup1) can be tested at the full alpha-level of 2.5% (one-sided). If H0(Sup1) is rejected at the alpha-level of ×0.2 alpha, then H0(Sup2) can be tested at the full alpha-level of 2.5% (one-sided).