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. 2017 Oct 11;6(10):e195. doi: 10.2196/resprot.7750

Table 1.

Calculated statistical power for varying sample sizes for two different survival scenarios, assuming no loss to follow-up.

Median survival timea Total N Power
9 10 .089
9 20 .128
9 30 .169
9 40 .210
9 50 .250
9 60 .291
9 80 .369
9 100 .443
9 120 .512
9 140 .576
9 160 .633
9 180 .684
9 200 .729
9 220 .769
9 240 .804
9 260 .834
9 280 .860
9 300 .883
9 320 .902
9 350 .925
9 370 .938
9 400 .953
12 10 .158
12 20 .269
12 30 .376
12 40 .475
12 50 .564
12 60 .642
12 80 .765
12 100 .851
12 120 .908
12 140 .944
12 160 .967
12 180 .981
12 200 .989
12 220 .994
12 240 .996
12 260 .998
12 280 .999
12 300 >.999
12 320 >.999
12 350 >.999
12 370 >.999
12 400 >.999

aCompared to a group of patients with median survival of 6 months using log-rank test for equality of survival curves. Power was calculated assuming equal number of patients in each treatment group, significance level at .05 in a two-sided test, and no loss to follow-up.