Sample size estimation for the diagnostic impact outcome comparing a combination of two antibiotic arms to standard of care arm (2:1 comparison)
| Power (X2 difference between independent proportions) | Effect size (50% SoC vs 60% amoxycillin or azithromycin) | Effective sample per arm (sputum negative participants needed) |
| 0.80 | 0.10 | 290 |
| 0.85 | 0.10 | 332 |
| 0.90 | 0.10 | 388 |
Highlighted entries indicates target power and respective sample size estimates based on knowledge of TB risk, ability to produce and submit sputum and loss to follow-up.
Stata code: power two proportions 0.5 and 0.6, test (χ2), power (0.80), n ratio (2).
SoC, standard of care; TB, tuberculosis.