Table 1 Total number of clusters and participants required for various cluster sizes
Number per cluster | 5 | 6 | 8 | 10 | 12 | 15 | 16 | 18 | 20 |
|---|---|---|---|---|---|---|---|---|---|
Number per cluster accounting for 20% drop-out | 7 | 8 | 10 | 13 | 15 | 19 | 20 | 23 | 25 |
Total clusters | 60 | 52 | 40 | 34 | 30 | 26 | 24 | 22 | 22 |
Total sample | 420 | 416 | 400 | 442 | 450 | 494 | 480 | 506 | 550 |