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Table 2 Required total sample size

From: Procalcitonin guided antibiotic therapy and hospitalization in patients with lower respiratory tract infections: a prospective, multicenter, randomized controlled trial

True assumed failure rate in both arms

Required total sample size

 

Δ = 5%

Power 90% (80%)

Δ = 7.5%

Power 90% (80%)

Δ = 10%

Power 90% (80%)

10%

1278 (932)

578 (426)

330 (244)

15%

1792 (1302)

806 (588)

458 (334)

20%

2232 (1624)

1002 (730)

570 (418)

  1. Sample size calculation for the primary endpoint, i.e. required sample size to conclude at the one-sided 5%-level that the disease-specific failure rate in PCT-guided arm is at most Δ higher compared to management with enforced guidelines with a power of 80–90%.
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BMC Health Services Research

ISSN: 1472-6963

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