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Table 1 Sample-size calculation

From: A pilot study of respiratory muscle training to improve cough effectiveness and reduce the incidence of pneumonia in acute stroke: study protocol for a randomized controlled trial

Expected treatment effect (L/min) Expected SD within group (L/min)
50 100 150 200 250 300
50 15 58 125 250 400 600
100 5 15 35 60 95 125
150 <5 8 15 26 42 58
200 <5 5 10 16 24 34
  1. Estimates of required number of participants per study group to give 80% power at the 5% significance level, according to different expected treatment-effect sizes and different expected group standard deviations (SDs) of the primary outcome (peak expiratory cough flow (PECF) of voluntary cough).