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RegisterPE at border of the AR: power ≤0.05! [Power / Sample Size]
❝ At GMR 0.8 and sample sizes <49 power starts to drop below 0.05. With n=12 it is only 0.0337.
Very nice and interesting 3D figure.
Nevertheless in practice power is almost equal to 0.05 at GMR 0.8000 (if you replace axis "sample size" by "CV" in the figure and the points (for each CV) will be calculated as for minimum required sample size, the curve with power 0.05 (almost straight line) will be approximately at GMR 0.80).
So alpha could be seen as less than 0.05 (with two decimals accuracy) only in pilot studies or in really underpowered studies. (If I am not mistaken.)
❝ Seems that I’ve forgotten my own “Don’t panic!” slide. In the dark ages I used to write in my reports “α ≤0.05” and “≥90% CI” and earned questions.
To the slide, the figure is for classical 2x2 design? It seems strange to me, especially curve alpha=0.0500, which is raising and I'm not getting why it's descreasing with n>56. Try recalculation at n=60, CV=35% (last minor tick) ... with GMR 0.80, the power will be 0.0500 (so this point should be under the curve 0.0500 and not above) or am I wrong somewhere?
Maybe I am just not understanding the slide without the comments presented in Barcelona.
Complete thread:
- Post hoc Power Jay 2016-01-08 06:49
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- Post hoc Power ElMaestro 2016-01-08 15:07
- Post hoc Power Helmut 2016-01-09 14:21
- Post hoc Power Jay 2016-01-11 10:59
- PE outside the acceptance range Helmut 2016-01-11 14:02
- PE outside the acceptance range Jay 2016-01-13 08:24
- Power for PE outside the acceptance range d_labes 2016-01-13 11:59
- PE at border of the AR: power ≡ 0.05 Helmut 2016-01-13 12:38
- PE at border of the AR: power ≡ 0.05 ? d_labes 2016-01-13 13:21
- PE at border of the AR: power ≤0.05! Helmut 2016-01-14 01:29
- UMP - uniformly more powerful test d_labes 2016-01-15 20:08
- PE at border of the AR: power ≤0.05!zizou 2016-01-24 22:12
- Smoothing artifact Helmut 2016-01-25 14:15
- PE at border of the AR: power ≤0.05! Helmut 2016-01-14 01:29
- PE at border of the AR: power ≡ 0.05 ? d_labes 2016-01-13 13:21
- PE outside the acceptance range Jay 2016-01-13 08:24
- PE outside the acceptance range Helmut 2016-01-11 14:02
- Post hoc Power Jay 2016-01-11 10:59
Ing. Helmut Schütz