Use PowerTOST [Power / Sample Size]

posted by d_labes  – Berlin, Germany, 2017-12-06 10:52 (2421 d 04:38 ago) – Posting: # 18037
Views: 14,464

Dear Astea!

❝ ...

❝ By the way, for extreme numbers from the paper by Endrényi L, Tóthfalusi L. we also get slightly underpowered study:

power.scABEL(CV=0.8,n=54,theta0=0.95,design="2x3x3")

❝ [1] 0.79917

power.scABEL(CV=0.8,n=72,theta0=0.9,design="2x3x3")

❝ [1] 0.79782

❝ ...


The sample sizes in the paper of the two Laszlos are based on 10 000 simulations (only).
Additionally the seed of the pseudo-random number generator for the sims was presumably different.
Try this:
power.scABEL(CV=0.8, n=54, theta0=0.95, design="2x3x3", nsims=10000)
[1] 0.7976
power.scABEL(CV=0.8, n=54, theta0=0.95, design="2x3x3", nsims=10000, setseed=F)
[1] 0.7995
power.scABEL(CV=0.8, n=54, theta0=0.95, design="2x3x3", nsims=10000, setseed=F)
[1] 0.8029


With nsims=1E6 and setseed=F on the other hand I don't succeed to obtain power>0.8 (20 tries).
One more reason to use PowerTOST's power.scABEL() / sampleN.scABEL() functions :cool:. Also w.r.t the tables in the paper of the two Laszlos.

Regards,

Detlew

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