Sample size:
We projected that 15% (27) of patients with AMI would have a history of recent respiratory illness, and therefore we required a minimum sample size of 396 patients to estimate this proportion with an absolute precision of 5% points and a 95% level of confidence at 80% power. To calculate the sample size, we utilized the power and sample size function in STATA 13 for Windows. The formula used was ”sampsi 0.15 0.10, power(0.80) onesample”. This approach enabled us to determine the minimum sample size required to achieve our desired level of precision and confidence in the estimation of the proportion of recent respiratory illness among AMI patients.