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POWER SIMULATION -- unmerge_d0_5   [metric: # successes (count)]
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model: behavior ~ stim + day + stim:day + (1|rat)   (behavior = # successes (count); day within-window)
observed groups: stim n=3, control n=3   nrep=120, alpha=0.05
ground truth: stim:day=+5.362/day, rat SD=4.853, residual SD=10.7, days=6

 true stim:day interaction = +5.362 (100% of observed)
  N/group  | per-animal power | LME power
  ------------------------------------------
  3        |  0.35            |  0.73  <- observed
  5        |  0.78            |  0.90
  8        |  0.97            |  0.97
  12       |  1.00            |  1.00
  16       |  1.00            |  1.00
  24       |  1.00            |  1.00

 true stim:day interaction = +2.681 (50% of observed)
  N/group  | per-animal power | LME power
  ------------------------------------------
  3        |  0.11            |  0.24  <- observed
  5        |  0.25            |  0.37
  8        |  0.44            |  0.46
  12       |  0.68            |  0.72
  16       |  0.79            |  0.81
  24       |  0.95            |  0.94

Read the per-animal column as the honest power; LME is optimistic (obs-level DF).