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. Author manuscript; available in PMC: 2014 Jul 2.
Published in final edited form as: J Cyst Fibros. 2011 Jul 30;10(6):453–459. doi: 10.1016/j.jcf.2011.07.003

Figure 1. Effects of Treatment Definition and Duration of Observation on Sample Sizes Required to Detect a Given Treatment Effect in a Randomized Controlled Study.

Figure 1

Sample sizes per arm required to assure 80% power to detect reductions in exacerbation treatment (as hazard ratios) in 1:1 randomized studies of 3 month (clear lines), 6 month (light gray lines), 9 month (dark gray lines), or 12 month (black lines) durations. Results for exacerbation treatment defined as administration of “any” antibiotics are shown as solid lines and those for treatment defined as administration of IV antibiotics are shown as dashed lines.