One hundred and eighty-three divisions met the criterion of a minimum sample size of 10 for calculating prevalence rates.
For the HCW branch of the study, the minimum sample size was calculated using the same criteria as for the community study.
Power calculations indicated the need for a minimum sample of n ≥ 110 for concurrent criterion validity and n ≥ 45 for reliability [ 52].
Additionally, often additional stopping criteria are defined, e.g. minimum sample sizes in the terminal nodes.
Based on the results of their health examination in 2010, 19, 724 subjects met the inclusion criteria and this source population guaranteed the required minimum sample size for this study.
Power calculations indicated the need for a minimum sample of n ≥ 110 (reliability, n ≥ 45; and concurrent criterion validity, n ≥ 106) [ 28].
46 We used three additional disease specific quality criteria: sufficient reporting of variability of results (disregarded when individual patient data were available), minimum sample size of 30 participants, and minimum study duration of three months.
Thus, we aim to eventually recruit a minimum sample of 170 participants with diabetes and ESRD from National Kidney Foundation (NKF) Singapore community dialysis centres (inclusion exclusion criteria as per qualitative substudy described above).
Criteria included: use of commercial NAATs on respiratory specimens for diagnosing pulmonary TB, comparison of NAAT result with culture as reference standard, information to calculate sensitivity and specificity, and minimum sample size of 50 to avoid selection bias [20].
Thus, applying the aforementioned guideline would yield a minimum sample size of 30 for this study, and the sample size (N = 235) is good to meet the required criteria for analysis.
